is it normal for hair dye to hurt this bad

i always go to the salon to get my hair dyed rather than doing it myself cuz my hair is thick (black to brown). it always stings so ig i assumed that’s normal since it is chemical after all. during my last visit though, i requested to dye it a more vibrant shade of brown, so they applied something to my roots first before the rest of my hair. i remember sitting there in the salon for hours in absurd pain, so much so i felt like writhing on the floor. anyway, it did come out a more vibrant shade of brown. upon going home, i realized my scalp was in so much pain; it was difficult to even get a comb to touch my scalp cuz it hurt. i developed lots of scabs(?) and blisters there…thankfully i’m doing fine now.

i’m planning to come back this weekend to get my hair dyed red. however, i’m getting a bit anxious after recalling the last appointment i had, the aftermath of which i now realize was quite terrifying. i’ve always assumed that hair dyeing is supposed to hurt, but in retrospect maybe the last one i had was not a normal amount of pain for a hair dyeing session…was it?

is hair dye actually supposed to hurt like that? is my scalp just too sensitive? would rlly appreciate some tips!