I have this one big pimple in the middle of my fairly-clear forehead, and it's been there for weeks. Any help?

I really don’t care how I look, and I this is usually the last thing on my mind. But this zit has been there for at least 3 weeks. I usually don’t get huge zits like this. I have tiny ones all over my forehead. This is getting really annoying. Does toothpaste work? If so, how would I use it? I really don’t want to go buy anything. I suppose I could if I need to, though.