So, firstly, try not to freak out too much and keep calm, but you should definitely get him to a vet ASAP as the gunk in his nose and physical symptoms sound kind of like he might have an RI (respiratory infection= "Cold" for snakes). These can be treated easily by the vet, but can become very detrimental for your ball if left untreated. I don't know about the whole squeaking part, but it does not sound so good to me- especially if it continues after he pooped. So, try to get him medical attention like now- again it may NOT be an RI as I am not a vet, but it is not worth the risk if it is one, I guarantee that.
However, after he gets medical attention, maybe these tips can help with your husbandry and prevent any medical issues in the future:
1. This first is more of a "preference", but can help with his stress levels: the open ended log hides that I think you have in there thare actually note greatest for little balls. In the wild, ball pythons spend their time in HOLES, completely surrounded and secure, which is where they feel safest (no surprise attacks from behind). I recommend getting him 2 hides that have all sides enclosed and just an entrance hole- you can either get cheap plastic ones on Amazon for like $10 or "fancy" ones that look like caves and such from Petsmart/Petco for around $15-20.
2. The second is how to help you with the humidity, which is actually what causes RIs if that is what he has (I don't think the rapid drops and increases in humidity you describing are good for him at all and humidity should stay consistently 50-60% and not fluctuate that much). Heat lamps suck the humidity out of the air, but for me (and it seems for you), I needed a heat lamp in addition to the UTH to keep up the ambient air, right? A) Putting the Hygrometer directly under the heat lamp may be causing the readings to be inaccurate, I would recommend putting the gauge a little deeper into the tank to read the air that is not directly affected by the heat lamp. B) This tip is GOLDEN if your humidity sucks due to heat lamp:
GET SPHAGNUM MOSS. This stuff saved my life as I couldnt keep the humidity up with the heat lamp. Buy a box from Petco/Petsmart for like $10- it is messy so be careful opening it. There are instructions on the box, but basically you'll soak it, let it dry and then place a couple SMALL patches in his tank. This stuff holds humidity like you wouldn't believe and has instantly solved my humidity problem- I only have to mist once every few days with the stuff and my heat lamp on a thermostat 24/7. You won't use it all at once, and dont use TOO Much at one time. Put a bit in maybe two small patches (one on cold side, one on warm side) somewhere that your ball won't normally sit directly on it cause too much humidity directly under his belly won't be good for him (scale rot).
3. If you're having trouble accurately monitoring temps/humidity, I really recommend getting DIGITAL thermometer and hygrometer- they are more accurate and maybe get 2 to get a wide-spread read from one end to the other. Zoomed has a product that has a thermo/hygrometer all-in-one device and two probes connected to each device to accurately measure each separately. Amazon has a 2 pack of this for $15 or so- put one on the warm side and the other on the cool side. This will give you accurate readings on both ends of both temps and humidity and put your mind at ease.
4. This is another preference and don't be offended, but since it was a concern I wanted to share MY experience (that others share as well) that can maybe help you. For feeding, if your ball isn't the best at "hunting" (which many of them actually aren't), you might need to change up how you're going about it. A) There's a big controversy about feeding in the tank or in a separate container. I think it comes down to the individual ball, so maybe you can test it out and see how he reacts. Mine will actually only eat in a separate container (I use a relatively small cardboard box big enough to fit maybe 3x the balls size and keep one half closed so she feels safe/protected while eating), but this also prevents accidental ingestion of substrate that you mentioned, which can also be very dangerous for them. Counterargument is that handling your snake after feeding to put them back in the tank will make them throw up, but mine never has- not once. Just wait 30 mins after he's completely swallowed and then slowly and gently put him straight back in his cage- total of 30 seconds of handling after feeding shouldn't be a big deal. Again, it comes down to the ball, if you're open to it, maybe give it a chance and see if it works for him and that may alleviate any stressful feeds in the future (my girl eats like a machine using this technique). You may also want to consider feeding freshly killed prey as they still get the benefit of "fresh meat", but if he is not good at striking at the right angle while the prey is actively running around, then he simply may not be the best hunter and health wise, it really doesn't matter to the ball if it was killed beforehand or if he killed it. The reptile store I get my feeders from actually pre-kill them for me no problem and I am able to feed her fresh prey, but eliminating the risk of swallowing the prey wrong or of the prey "fighting back" and injuring your ball.
Just some food for thought! Good luck!
