Instead of botox for a long horizontal forehead wrinkle, can a laser be focused along the inside of the line to then cause a scab, then heal?

Not likely: Forehead wrinkles tend to be deep furrows rather than the superficial wrinkles for which laser is best suited. The only way to eliminate the furrow is to eliminate the cause, i.e. Contaction of the forehead muscles. Botox or a similar paralytic is the best way to accomplish this.

Dynamic wrinkle: the movement of the muscles in the forehead cause the wrinkles which are best treated with a neurotoxin. Laser therapy may reduce the line a bit but cannot achieve what a neurotoxin does.