i can understand your concern.
its an allergic reaction
to the bleach most likely.
i would recommend that you apply mometasone
furoate cream over it twice a day for a week. this will help the inflamation to settle down.
take tab. levocetrizine 5 mg once at night for a week in case of itching.
once the reaction subsides, you can allow the skin to heal, after around 2 weeks, if its still dark, you can use glycolic acid
6% cream at night on the affected areas.