looking for this manga

I read this manga in like 2020 or so, it was very dark and fucked up, also only had a few chapters out at the time. Follows a teacher who is very well liked, I think he was secretly gay (I don't think it was a bl tho, more of a psychological horror type thing, but maybe it's tagged as one). The teacher ends up seeing one of his students in an adult video, the whole thing is very disturbing. This student is a truant and has a lot of bad rumors about him, and isn't very well liked. The teacher ends up doing a home check in on the student due to the truancy or rumors, and the student lives with his grandma (?), who I think says some bad shit about the student to the teacher. The student is also self harming or something and I think there was some horror stuff implying he might not be human or something. Sorry if my desc isn't accurate, I was like 14 when I read this so I don't remember much. Overall it was really messed up but I randomly remembered it and am so curious on how it ended