in general, what helps me is to acknowledge the uncomfortable thoughts i have, and then tell myself i will think about them later. that is one way to dismiss the thought, without completely avoiding it. sometimes i forget all about the thought (thats the goal with that technique lol). if not, it can help to write about it in a diary, or talk about it to a trusted person. basically the point of that is to get you and the obsession out of your head n out into the real world. the obsession wont last forever, which is a helpful thing to keep in mind for me. and once you stop it from having power over you, it will fade away.