Risk of hair dye/bleach chemical on human head (brain, scalp, etc.)?

2 weeks ago i went to salon to fix the color i put on my hair, (i put blonde and forgot that i still have my previous black dye on my hair) so they suggested to put bleach first if i wanted to continue putting blonde to the rest of my hair so 1hr45mins bleach on my hair followed by 1hr30mins blonde dye but still not getting the expected result so they decided to put a darker color so another 30mins more for darker brown dye, almost 3hrs chemicals on my head that it hurts my scalp really bad, i told them to wash it immediately but since theres so many people going to that salon, rinsing your hair would make you wait for your turn, u have to be in the line.. when i went home i was really disappointed for not having my blonde har done so i decided to cover it with the blackening shampoo i was once used to make the new color balance to the old black dye.. and now after 2 weeks, my scalp sometime oh most of the times almost everyday, i feel this goosebump-like numbness on my upper left head 3 inches above my left ear.. im afraid. is it possible that the chemicals used on my hair that day had harmed my brain or anything inside my head? please help me im really worried. will it be temporary?? is it only because my scalp was traumatized, will it ever be back to normal?? and not to feel that numbness in my head again??? please help me, dont have enough money to have any body test in the hospital, atleast give and spare me some knowledge and possibilities pls!!!!