I could see dabs eating away at your esophagus, especially the homemade crap most people get, or because they dab too hot or something but I don't see how it would damage your stomach. Only thing I've ever experienced with too much THC is a nervous stomach, I think its related to anxiety. I mostly only smoke joints and use edibles, used to dab a lot more but got tired of it. Joints get me more stoned and last longer anyway.
Funny antidote about that, I said that to a tender at Kind Love and he said something like, "You need better dabs then". And I'm like, "well I get all the fire terped out GreenDot black label when you guys get drops(basically the best most expensive extracts they get)." lol. I love the taste and get pretty high for a few min but even the crazy LR terpy slurpee runs don't last very long for me.