Swollen digits can be anything from an insect sting to a serious infection. Tenderness signals a more serious condition. The blistering rash sounds like contact dermatitis. If persists, an allergist can do a test to look for a cause. Might try OTC hydrocortisone cream on the blisters to see if they go away. Itching is more consistent with an allergy, pain is not.

Jesse P. McRae