I am a Protestant Christian, and I fear that I might be in the wrong religion and might go to hell. Is it possible for me to overcome this obsession in a way that still allows me to believe in absolute truth, I.e. that there is only one right religion? Because I would rather continue being OCD than give up the exclusivity of Christ’s claims.

There’s really no way to tell which religion is right and not, and that’s coming from a Catholic person. We just have to have faith in whatever we are doing.

OCD treatment has nothing to do with what you're allowed to believe. Treat the OCD then assess what you believe. If you were able to follow your religion without having OCD once then you can do so again. However treating OCD at all does require entertaining the idea that your fear is true so that your brain can become accustomed to it. You don't have to accept or internalise the fear as being true, but you have to take the possibility that it might be seriously, in order to treat your emotional and compulsive responses to that possibility. Once you're accustomed to the idea to where it doesn't give you much anxiety whatsoever, all triggers of it should only cause minor if any anxiety. You'll be free to choose what you believe just as before, and if you get intrusive thoughts of your fear again, then because of the treatment they won't be so emotionally strong and cause so much anxiety. You will have to give up all of your compulsions of analysing scripture, trying to figure it out, asking for reassurance, praying when you feel anxious about it in order to feel reassured, praying for forgiveness about not having certainty, etc. Any other compulsions you do. You have to give all of them up forever. If you start doing them again after treatment when you get a doubt as a way to make the fear and anxiety go away, your OCD can re-develop. And as Billy said, you can't have certainty that your religion is the right one. You have to give up any hope of ever having absolute certainty. Treatment won't give you certainty, continuing in your OCD won't give you certainty, and you're very unlikely to develop certainty post-treatment. Attempting to be certain is a compulsion which will make your OCD come back. The answer is that you can do treatment and still believe that there is only one right religion, yes, you just can't get any certainty that YOUR religion is the right one. It'll be tougher on you and make the OCD harder to treat than if you were willing to be less black and white about it, because relaxing our underlying beliefs can make our fears less threatening and thus easier to face and treat. It can still be done of course but it would take a lot of courage.