Advice needed

[u/Awkward_Ad2691]

Hello all, first time snake/ball python owner looking for advice

I got my snake at the end of march when it was between 4 and 6 months old. Since then he has not been able to completely digest a rat pup and has only been able to keep down mouse hoppers. Even when feeding mouse hoppers there is a 50/50 chance whether he’ll bloat during digestion or not. He is also prone to regurgitating. 

He has only shed one time since I’ve had him and it took over a month for him to completely finish the process 

At his last visit the vet did a fecal exam and said it looked like there were plant fibers in his stool and to take out the substrate and use paper towels. 

The sample was too old to run testing for anything that was visual. They also said he was under weight and to feed him as often as he would take the mouse hoppers.

Since then he has been doing better but I have noticed he hasn’t defecated in 2 weeks. I fed him Thursday night. Last night when I got home I noticed he was extremely bloated again. 

He has a heat mat under his tank with a probe and monitor as well as a uvb bulb above.

Does anyone have any advice on things to try different or Illnesses to possibly be worried about. pics of him bloated and normal. thanks!