You know what, there was another thing I wanted to say, It also might sound silly. i just want to share as many tools as I can. You mentioned this person was in your head and I can relate. I want to talk about it using a different example.

Recently I had the Pokemon theme song stuck well and truly in my head. At first I was happy to have it there and then it got too much. I needed it to go but couldn't replace it silence. So, eventually I replaced it with other songs. I had to choose the songs carefully. Songs with the same energy but different shapes. I chose 80s power ballads like "Final Countdown" and "We Need a Hero". Now all of the songs live together in harmony and I can draw on all my other genres when I need them.

I still struggle with people in my head. Most people I know really. It's kind of a trait of mine even on a good day. Changing the song in your head is easier. But, from where I am, in my process, it's kind of comparable.