New Purchase Issues

So I just recently bought a pastel from sewerfest reptile expo in racine, wi about 2 weeks ago. He seems healthy apart from the fact that he has pooped about 6 times since then. At first it was runny and I read that it can be common for young snakes to do this after purchasing them from a show. I fed him about a week after I got him to so I could let him settle in and he ate no problem. He almost seems to be losing a bit of weight with all this happening and I was just curious if there was anything I should do. Should I worry about internal parasites? How would I know if he had them or is this just something that will pass with a bit of time and more food?

Take him to a vet and have a fecal done so you will know for sure.