What is the average healing time for a pimple?

Healing time: It depends on the size of the pimple and what caused the pimple. On the average it takes 10-14 days.

Varies: The time for an acne lesion to resolve varies greatly. Surface whiteheads might resolve very quickly, while a deeper red "cyst" might take weeks or months to resolve. Although you didn't ask, i'd suggest consulting with your dermatologist if you're having significant acne problems. They can assess they type of acne you have and review appropriate treatment options.