I’m scared for my boyfriend to find my self harm

I can’t believe I have to make this post I don’t know what’s wrong with me. I’m 20 and soon starting a job in a first responder career. I have been so stressed out to the point of sh on my thighs last night, I haven’t done that since I was like 14 I don’t even know where it came from.

My boyfriend is 8 years older than me and a blue collar worker. We have been together for one year. He doesn’t really understand mental health very well, or at least doesn’t talk about it with me.

I am so scared for him to find the cuts, I feel like it will make him scared of me. I don’t know what to do because we are very sexually active and it would be very strange for me to decline sex as I never do that, but I also don’t want him to see them during or before it. Has anyone been in this type of situation before with a partner that didn’t really support you in that way I really don’t know what to do. Are there any blue collar workers in here that could give their opinion on what I should do as well? :(