Need help Savannah not moving legs

Really could use some advise. Bought this monitor last week. Yesterday When I when i went to change his water he was a totally different lizard. Before he was very active, aggressive, he bites and tail whips and moved with great agility. Yesterday when I put my hand in his enclosure he did not hiss or get aggressive. I slowly moved my hand over to him and he slowly moved away dragging his back legs, also his right front foot just stay bent under as he moves that leg. He is very lethargic with little response. He is also small for his age, I think. 13" and long and 78g and he is suppose to be 11 months old.

My question is can physical symptoms of MBD just show up over night. His substrate before I got him and currently is paper so I don't think he impacted. He came with a UVB bulb but I replaced with a new one. His basking temps are 110 and 80 on the cool side. I keep his humidity at 70%.

We have several reptiles and I never seen something like this happen so quickly

He has not eaten much since I got him but that didn't surprise me. Like wise he has only gone to pee and poop a couple of times.

Hey :).
I frequent this forum, but decided to join as I noticed no one had replied to your answer yet. The monitor sounds extremely emaciated, dehydrated, malnourished, and may possibly have organ failure and gout. It would be at least a year old now, and should be at least 2 feet and weigh a significant amount more for even it's current size. My guess is poor husbandry from improper care is finally catching up. Most start to shut down after about a year of improper husbandry, however some die much sooner, and others linger on for a few years.
The setup you described does not sound even close to accurate. Give savannahmonitor.co a read. Great site with lots of good information.

I highly doubt this one will make it, but the first thing is to get it into a proper enclosure asap (as in now), and ring up the vet to check for organ failure and gout. If they come back positive, the outlook is very poor. If not, the little one may have a chance.