Hi welcome to health care magic forum,
induced rashes occurs after 1 or 2 dosages of medication.
After 10 to 12 days post medication rash is rare .
It could be any skin lesion like eczema
or urtricaria .
You can take an antihistamine like fexofenadine
). You can use local ointment too for 1 to 2 days .
If no relief than see a skin specialist for further evaluation and treatment.