antibiotic fail? allergy?

We took LB to the dr again Thursday morning b/c he had this 101-102 fever for over a week (we took him the day after he got it b/c he had been sick for 2 weeks at that point and they told us he probably got another cold).  This time the CPNP (not the doc) took a look at him and cleaned some wax out of his ears and could see he had an infection in each ear - poor guy!

So she gave us a script for Amoxicillan and we left.  I dropped him back home with MH, dropped off the Rx, and went to work.  Picked up the Rx on the way home, gave it to him around 6, then dropped MH off at class and ran a couple of errands so that I could watch him.  He's not been on them before, so I was worried about a reaction to them.  He seemed fine and we went to bed a little late, 9:30, but not too bad. 

He woke up around 1:30am, just crying uncontrollably... we finally got him to settle down by putting the tv on and one of his favorite shows and rocking him.  Once he settled down, I noticed his left eye was swollen... looking at the Amox papers, one of the side effects was swelling in the face and to seek immediate medical attention.  So....... we called the ambulance, and LB thought that was awesome.  He totally forgot about whatever pain he was in!   But they took him to the ER and we were there until about 4:30.  They said they didn't think it was a reaction to the Amox, but they gave us a different antibiotic to be safe. 

So, he's been better since taking the other antibiotic (Azithomycin I think?) and we had a good weekend.

My question is, should I tell his pediatrician that he's allergic to the Amoxicillan next time we go?  Should I just call them and tell him about the reaction?  I haven't called them yet to tell them we were in the ER, b/c we were all so sleepy on and off on Friday and we were away over the weekend.