How do i get rid of a huge pimple on my forehead overnight?

Wishful thinking: To paraphrase, anyone who tells you they can rid you of acne overnight is selling something. Acne is a problem of months and years. There is no quick fix. There are good treatments to be had at every drugstore starting with benzoyl peroxide creams and mild cleansers. For a single pimple, try a hot shower and then a warm wet compress, if ready to drain, can help. Don't scratch or pick.