ALT key issues

[Medic]

I've been having issues where I need to press my q, r, y, p and blue dot buttons harder in order for them to work. Today I took it in to a sprint repair center to get it checked out and they tell me they can't cover me under warrenty because there appears to be water damage. I have never dropped my phone in any water. The guy told me that even sweat can cause this. No this sucks cuz I live in south texas where its usually 100+ and I carry my phone in my pocket. There are times where my screen gets condensation from being in my pocket.

Do any of you think this might be an issue for your key problems?