I had my hair dyed chocolate cherry brown matrix loreal and I got a bad chemical burn, what should I do?

Wound care. Apply aquaphor or vaseline to the wound until completely healed. Use topical antibiotic if you get blisters or open sores. See a doctor for oral antibiotic if develop signs of infection.
Chemical burn. Tincture of time will do wonders along with the use of a steroid ointment applied 2 or 3 times a day. Then refrain from doing it again.