When my bp gets squirmy his scales will catch on my nails and I always feel bad, I started cutting my nails shorter so it wouldn't happen as much. If you rub your bp from tail to head at all you will feel belly scales catch your fingers, which is probably a little unpleasant for your snake but won't hurt him. I suggest you fix your humidity first, allow him to have a good shed in proper humidity, then examine him again. Of course that does not mean ignore the possibility of mites, but don't freak out just yet.
To help with your humidity you can try any or all of these:
1. You can purchase a small humidifier for $20-$30, and it will work wonders in a small-to medium sized room. I use a no-mist humidifier and I have it on a shelf just above my tank. 60% humidity almost always:)
2. Seal the top of your tank 75%, and leave 25% open for heat and ventilation. Use a water dish that has alot of surface area. Place the water partially over a controlled UTH to help the water evaporate into the tank.
3. Cover the top of your tank with a damp towel (a tea towel or a small hand towel). Wash/switch the towel every few days and when you soak it once a day, rinse it with hot water and soap to help prevent bacteria from building up.
****It is very important to properly measure your humidity. Use a digital hygrometer - dials stick and can be VERY inaccurate. A digital hygrometer costs about $10 at Walmart or Home Depot, and you can buy thermometer/hygrometer combos. This is a $10 investment you won't regret*******
