"Going Down" (1985)
http://www.iafd.com/title.asp?title=...Down&year=1985
Here are 4 caps of the "haircial"...
It's not the only time Peter shot on Jessica's hair, there is a similar scene in the 1986 movie Teenage Games, in that one he also shot on her back, and onto her hair which was tied into a ponytail. Guess he liked her hair