You aren't on an oral med? Allegra, zyrtec, etc? Only the astelin? And how big was the redness/etc at the injection site? Anything quarter size or smaller I wouldn't worry about...but I would get on an oral med..at least for the day of your injection. If you have allergies bad enough for injections, then either you should be on something more than astelin or I would question your choice of physicians.