My child got the 3 Rocephin injections in a row (one per day) when he was about 2-1/2 same as yours. The first day wasn't too bad, I gave tylenol just before went into Dr. office all 3 days. Second day was about the same, though he was more aware that we were at the Dr. office again, by the third day it was hard to get into the office since when we pulled into the parking lot he already knew what to expect. So that one was the worst one. Even at that age they can figure it out! They should use lidocaine to dilute the powdered Rocephin b/c yes the shots are painful and so the lidocaine will help numb some. I don't remember him having any problems with soreness, etc and he was fine after the initial injection (similar to vaccine shot). Course let him run around and all like normal so any soreness will work itself out. Also we had to wait 30min in waiting room (they gave us a timer set that we had to give back to make sure we stayed the whole time) to make sure no reaction all 3 days. So bring his favorite lovey and a few books that you can read to him while you cuddle and wait. Good luck!