How long will it take to see if your allergic to hair dye?

in 2 days the fluid flowing from your head will be gone if the doctor has given you some ointment. (it hurts. >.<) but nevertheless, you will still experience swelling until day 5 or 6. my doctor gave me prednisone and some anti-histamine as oral medications. but so far i'm on my 9th day

(did not take any medicine from days 7 to 8) and still some fluid is comin out in my scalp. very irritating. >.< if you want to take a bath be sure to use super cold water so it would not open the healing wounds. i hope his answer would help you.