burm concern please help

[dylan2b]

hi everyone,
I bought my first burmese python earlier this week. He is a 3 month old who is eating well and seems to be healthy, with one exception. His skin is VERY loose. Its almost like he is in the middle of a shed, but I know he is not. I have had many snakes before, but I have never seen anything like this. He is being housed properly now, but the pet store I got him from is quite unsanitary. He was being housed in a 20 gal. tank with another burm, 2 retics, and two bloods, all of equal size. The substrate was little pebbles, and the water was not fresh. SO, does anyone have any ideas on what might be wrong with his skin or how I could get his skin firm.

Thank you so much for your time, sorry for the long post.
Sincerley Dylan2b