multiple (small) spots/marks on sides of iphone 12 pro

After taking off my clear case to clean my back and the sides of my phone, I couldn't clean the sides. I tried searching up the cause of it but it was neither errosion or a stain (at least, it didn't look like that to me). Normally it would go off easily from the past cleaning sessions. However, this time it looks like these spots/marks are "carved" into my phone and even with the recommended products from ape (isopropanol etc.) it won't go away.

The spots/marks are on all sides of my iphone 12 pro, even on the buttons. What is the cause of it and what should I do?