Can salonapas pain patch or pain creams cause irritation , itching to the skin and blister if left on too long? or allergic reaction? treatment?

Yes Salon pas: commonly has aspirin (salicylic acid) which is a common skin irritant if used repeatedly in the same location. Also, the material the patch is made of can cause a local allergic reaction. Treatment for blistered skin is make sure it is free of irritant, lightly washed with mild soap or just water/vinegar combination, and hydrocortisone applied to site.

Pain patch: The pain patch is not to be used for greater than 3 days, or if you are sensitive to any of the ingredients. It is not meant to be used while you are sweating or on damaged skin. A contact or allergic dermatitis is possible. If you feel like you are having a reaction, remove the patch and wash the area with soap and water and do nothing. Avoid contact with irritant. Visit MD if no improvement.