It seems that you may be having irritant contact dermatitis
due to African soap.
Due to irritation, you developed dry,black and burn like skin.
There developed discoloration.
You immediately stop soap use.
Take antihistaminics like levocetirizine
if you feel itchy sensation.
Take a short course of steroids.
Apply emmolient with mild steroid cream.
Avoid sun exposure.
Do not apply cosmetics.
After normalisation of skin, apply kojic acid
containing cream and vitamin E cream.
Take vitamin C for long time.
You may be benefitted.
However, you consult dermatologist
I hope you got my answer.
Dr. Ilyas Patel MD