I've heard that they can take several weeks to a month to adjust. I did not have this problem.
From my research before getting Louie, and my work with Louie, 120 is a medium temp for his basking. I have him a long sloped basking area under his MVB which gives him a range of 110-130 along that basking brick. The rest of his cage (he is in a 4x2x2 enclosure I built him) ranges in the high 90s/low 100s around his basking brick and down to the low 80s (almost room temp) on the colder side of his enclosure. He spends most of his time under or on the ground beside his basking area, but when he is actually out basking he is at the very top (130 degree area) of the basking rock. He spends very little time in the cooler side of his enclosure, but will go over there when he's running around or whatever.
I am by no means a uro expert - from just having one uro for less than a year so far but I appear to be the only one answering soooooo... I have a couple questions:
What size/type of enclosure is he in?
You said he is in a tank - are all the sides of his tank exposed?
I've heard of covering all sides of his tank with paper for a week, so he can get adjusted, then removing one side at a time until they get used to it. I used an opaque tub with Louie at first for the adjustment period, but then when I put him into a tank but he was very stressed by seeing movement around him all the time and things coming at him from above. I found that when I switched to a wood enclosure with a glass front it changed him tremendously because this way he can see me coming (and run if he wants to) and also all but one side of his enclosure is covered so he doesn't stress about the things coming towards him from all sides.
What kind of light are you using?
UVB is extremely important to these guys - I used a poor quality MVB one time and it didn't work out so well at all...
What are you feeding him?
Perhaps you could try going back to the store and finding out what exactly they were feeding him (and you can find out what these tortise treats are). It is possible they were feeding him something different than you are - I have seen a lot of petstores feed just spring mix or mixed veggies or even just romaine lettuce, whereas you may be feeding him something different that he is not familiar with (even though it is better for him...)
Just a couple thoughts. Answer those and I'm sure I can come up with more
