I can totally relate my cham has a vitamin a problem and is currently producing excess keratin and pushing it out of his eye turrets, I know weird. This made me so sad and mad and I felt like everything I have ever done was for nothing and that I was a failure but I realized that the battle is...
Oh for sure I have complete confidence he will make it especially with someone like you taking care of him! I've been there and its scary but just remind yourself you've kept him alive this long and trust your judgement with support of our fine fine friends on these beautiful forums!
You got this! I've been there feeling sad and all that about my cham thinking I've done everything wrong but it gets better, don't beat yourself up and talk to someone to feel better, at least that works for me.
I would second never cutting a chams nails and even if it did break I would let it fall off unless it gets infected or something but I'm glad this is not the case! Good luck!