Like kaorte said, the 29 gal tank for a hatchling could cause stress. If you already have the 29 setup for the snake, go to walmart and buy a 6 qt tub, in my area they are 97 cents. put air holes in it and get the paper towels that are half sheets. they fit the tubs nice without having to fold. give him a bowl of water and place the tub inside the 29 gal tank partly on the heat. in a few months when he out grows the tub, cut a hole in it and use it for the hide. this makes the moving to a larger size enclosure less stressful on the snake since he been in the now hide for months already.

Why take the snake to the vets? He is on the small side even for a hatchling and moving him to the vets and the handling of an exam that he most likely don't need could throw him off feed again. at his size, he's eating, keep him eating, don't pound him with food right away. let his body adjust to eating and slowly increase his intake. after a few meals 5 or so, look him over yourself and check him for mites since he came from a pet store. if you're not sure about anything, the members on this site will let you know if vet care is needed. good luck you will do fine, don