There are two big reasons why this comes up often:
First of all: Your brain is part of your body and it changes just like any other part of your body. Lifting weights once won’t turn you into a bodybuilder. Likewise, practicing Acceptance once won’t transform your brain. Like physical exercise, it’s something you keep doing if you want to maintain and improve your mental health.
Consider how many years and how much energy you’ve invested in OCD. Now it’s time to invest the same energy in recovery.
Recovery is a lifestyle, not a lobotomy, so it’s about living and adding things to your life, not taking things away. The more you do it, the easier it gets and the more benefits you’ll see, just like a consistent physical exercise routine.
The second big reason for running into this, is some potentially hard-to-swallow information: You haven’t practiced acceptance and cut out the compulsions, or else you wouldn’t have a problem with the thoughts being there.
It can help to see intrusive thoughts as a set of compulsions we engage in around thoughts. That stuff in our heads, it’s just brain stuff. There’s nothing intrusive about it unless we start judging it and yelling at it, telling it to leave, that it shouldn’t be there, that it’s intruding.
On top of that, if we really want to get rid of it, and we like it when we don’t have those thoughts, then it’s totally natural for the brain to give us more of them. Why? Because they’re necessary to get that relief we’re craving.
As long as we judge them, hate on them, try to avoid and control those thoughts and images and voices and whatever the brain throws up, it’s going to keep on doing it.
So it’s way more useful to welcome whatever experiences we have up there. We don’t have to place them in charge of our actions.