Red Opium.

Hm, alright. Well, all alternatives don't work for everyone.

Next time try another, if the ones below don't work, there are plenty more.
It's hard to stop and get used to an alternative & find one that works.
I still don't have one yet... but others have found one that works quick, it's different with everyone.

-draw on your arm with a red marker where you would harm
-rip up paper
-draw
-talk to a friend
-snap your wrist with a rubber band
-cut into something - not yourself of course! try carving into fruit or something.