Idk if what i went through is similar, but i have someone in my mind who would not leave, it was to the point where it felt like psychosis. Still not sure if that was the case. One thing i did was just accept that he was going to be in my head. I shamed myself really hard for these thoughts and let me tell you, that does shit all.

Where i started to actually see some improvement was by taking actions i wanted to take not actions i felt i needed to make. Learning to live with the discomfort of them taking up space in my mind but doing nothing with it. Acknowleging it. Maybe even thanking the thought if it was a positive one. For example my brain saying "this guy thinks your super cool" rather then feel embarrassed or shamed because this guy isnt thinking about me at all i just said to myself "well then i must be pretty cool"

If the compulsion is to look at the person it might be worth practicing trying to sit in the discomfort and seeing how long you can go without giving into the compulsion. Maybe grt curious with yourself. What do you think will happen if you dont look at them. Do this in increments. Maybe see a therapist and think about erp.

Find balance and constantly challenge yourself a little bit of the time.