pip - rash

So, my child has a severe allergy to peanuts.  I was dumb and let him have a (full) strawberry shake from Braum's yesterday as a treat.  I even made sure they used a new scoop to dip up the ice cream, but not a half-hour later, this is what his face looked like.  That was almost 24 hours ago and it's not getting any better.  I've given him 2 full teaspoons of benedryl over the 24 hours.  Should I just keep dosing him on benedryl?  Hydrocortisone?  Does this even look like an allergic rash, or could it be something totally different, like Fifth's?  It's on his upper back and upper chest too.  He did walk through the woods with Papaw the same day...  Should I just ignore it?  If it's still there tomorrow, I'll likely call the nurse line, but of course, it's Sunday.  He doesn't seem too bothered, but it looks angry.  This picture doesn't do the redness justice.