is not herpes zoster
The possibility is scabies
..you may be right.
It might be irritant or allergic contact dermatitis
First , you take treatment for scabies.
Permethrin cream application at night and ivermectol tablet 12 mg at one time would clear the lesion...if it is scabies.
Otherwise go for anti allergic treatment .. Antihistaminics and steroids in tappering dose will improve the condition .
Consult dermatologist for firm diagnosis and tratment.
Dr. Ilyas Patel MD