What is a fast acting trick to get ride of acne on the forehead and chin?

Rx meds. Over-the-counter and pop remedies don't work well. I start folks on topical Clindamycin with or without an added retinoic acid derivative. If this fails, consider adding a systemic antibiotic that's right for you (erythromycin, tetracycline if you aren't going to become pregnant). This generally gets adequate results; dermatologists have "big guns" for the most severe cases.
Prescription meds. Prescription medications containing combination products such as benzoyl peroxide and Clindamycin can be very effective. Brand names in this category include acanya and benzaclin (clindamycin and benzoyl peroxide). Ofcourse, it also depends on the type of acne you have. If your acne is primarily comedonal (i.e., white heads and black heads), an acne facial combined with topical meds containing retinoids (such as veltin) also work.