Can Botox cause anaphylactic shock?

I have taken botox(Allergan) 40 unit. 6 hours later I have uncomforted breathing while I slept . But I thought it only side effect. 0n 14 february 2015 I have received botox again.But only 5 minutes I taken botox 12 unit. I have flushes , uncomforted breathing and palpitation. Dr. have taken Dexamethasone intra vein stat dose . I still have uncomforted breathing last night but not too much. So I thought I am allergy for botox !