Hello BumBum81. nice to meet you.
Make an appointment with your doctor and tell him/her what has happened to you.
A rash like the one you have is definitely sounding like an allergic reaction.
If you have to continue on this medication there is a topical steroid cream you can use for the rash.
I have to be on a medicine I'm allergic to (rash under my arms) as it's the medicine
that works best for my pituitary gland (which they only make 3 meds for and I've tried the others) and I use
a topical steroid cream every other night.
However, with Asthma there are plenty of other medicines you could try, so don't give up...
So get to your doctor and then let us know how things went...you'll probably be given another med to try (no big deal there)....
we will be waiting for you return response.