Hi, thanks for using healthcare magic

There are different potential causes for the blister you are presently noticing:
It can be as a result of an insect bite- these commonly result in these symptoms

Contact dermatitis which is an allergic reaction of the skin to something within the environment or something applied to the skin, also present with itchy blisters

Infections such as impetigo which is a bacterial infection that is , in most cases started with an insect bite that progressed can also cause your present complaint

Blisters can also occur in other conditions such as autoimmune diseases . This would include conditions such as bullous pemphigod. these blisters are more common on the upper arm and thigh but can occur anywhere.This is treated by apply steroid creams, in some cases oral steroid may be needed.

Infections such as chicken pox- this however would normally be associated with wide spread blisters on different aspects of the body

Herpes zoster also known as shingles-this occurs in persons with a history of previous chicken pox, it can present with a localised lesion however there is usually alot of pain with shingles.

Despite the different potential causes you can consider using an oral antihistamine and topical mild steroid cream to relieve your symptoms. Oral antihistamines are available over the counter ,the drowsy ones like benadry are stronger.

You can obtain a mild topical steroid cream like hydrocortisone which is usually available without prescription. If this is ineffective then you may need a stronger one which may require a prescription from your doctor.

It would be best,if possible to resist itching it because then it could potentially become bacterially infected if it is not already because the bacteria on the skin would enter into the blister.

Signs of bacterial infection would be pain, redness, increased warmth, swelling and discharge.

I hope this helps, feel free to ask any other questions

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