Remove the rubber buffer from the head attachment.
Degrease it with some soapy solution under running warm water.
Dry it thoroughly and disinfect it with alcohol.
Then, put it back on.
Latex Allergy
Can natural rubber cause allergies?
Rubber can trigger a latex allergy, which manifests as skin redness. In the presence of such signs as rash, itching, and swelling, treatment should be paused. Alternatively, therapy can be continued by wearing clothing.