How long after facial hair bleach could there be an allergic reaction?

amino

I used a mild facial bleach for the first time on lip peach fuzz. I did a patch test on my arm and waited an hour ino I should have waited longer but my sister gers married Thurs Fri so I didn't have time. I did it last night and it looks fine I iced and ran cold water over the area when I had done along with a soothing moisturiser. I've took an antihistamine this morning. I haven't seen any negative effects I just feel stupid for doing it as it says online u can get permanent damage. Can anyone who knows abou this advice me on what to look for