Possible allergic reaction to amoxicillin in toddler?

My 1yr old is almost done with a ten day round of amoxicillin after a bad bout of an an ear infection that doesn’t seem to want to go away (partly due to dealing with molars as well), and recently on day 7 he’s developed these red spots that aren’t red or bumpy on his arm and back of leg. He also threw up but I suspect it’s because he’s been doing this behavior of sticking his hand in his mouth as of late. I have a doc appt with him early morning to see what to do. My son also has ezcema but this doesn’t look like his usual bout. This looks like a rash but I haven’t seen him scratch at it it just suddenly appeared and I only noticed when I was recording my him to send a video to his grandparents because of how random it appeared overnight.