Okay so I bought a Guinea pig from the pet store the other day, I have watch so many videos on Guinea pig with mites, lice, and rig worms. What it looks like is that my Guinea pig have mites. It’s near his butt, looks like he has been scratching at it, and has been losing hair. So my question is how much childrens Benadryl I should give him? I don’t know his weight. He’s a small Guinea pig a baby, and also is it save to give him ivermectin paste? If so how much and how often.