what should I do im scared?

Ok so here the issue you may have seen my last question about how to tell a guy you dont like him well there has been alot happen sence I told this guy that likes me that I have a boyfreind for one thing befor I knew he liked me I thought he would be a nice freind so I made a mistake of giving him my cell phone number ok so what happened what a few nights ago I got a text at 1am saying good night my love I was upset he didint get the picture but let it go but today in science he came up to me and started talking to me I was nice to him but didint realy say much anyway he had a big cut on his arm and said hey what dose this look like? I looked he had my initails scratched on his arm not just a little scratch that was done by nails im talking like a big scratch that has alot of dryed blood on it! Now im scared and realy creeped out what should i do? Have any of you ever been in a situation like this? if so tell me about it and what you did thanks!