Diaper rash & first tooth

The amoxicillin has given Dash a raging rash. A girlfriend suggested that I try Burt's Bees diaper ointment, and since I had a tube, I tried it. The herbal smell was so strong that I decided to stick with the Boudreau's Butt Paste that we normally use. If it's still bad in a day or so I'll try pure zinc.

The poor little guy has been screaming bloody murder & some diaper changes require both AJS and I holding him down and he still manages to almost wrestle himself off the table along with the diaper, the changing mat, and anything else he can reach with his feet and hands. He's torn the edging off of the window screen. The changes are taking 3 or 4 times as long with having to retrieve everything on the floor, trying not to get kicked or punched in the face, and attempting to cover his rash with ointment.

He's also cutting his first tooth! I've been attributing the diaper rash to the amoxicillin, but would cutting a tooth have anything to do with it? I've been giving him Tylenol all weekend, because he seems like he's in so much pain.