If you taking medicine can rashes appear even though you trying to get used to the medicine?

I have been taking all these sets of medicines from a bad tooth infection but don't know which I'm breaking out in rashes. It's the same medicine I have been taking in the hospital but I didn't break it rashes because they have been giving me benadryl through the needle before taking medicine maybe?... show more I have been taking all these sets of medicines from a bad tooth infection but don't know which I'm breaking out in rashes. It's the same medicine I have been taking in the hospital but I didn't break it rashes because they have been giving me benadryl through the needle before taking medicine maybe? I break out in a rash on one spot then it go away then appear in another spot and then go away. Do my body have to get used to it or something?
2 answers 2