Would my teacher understand this situation?

My year head / dean in school has helped me through almost everything I have had problems with and he has told me that I should never hesitate to come to him that his door is always open that he is there to support me, but also that I should try to sort out strategies for myself. the situation is as follows.. A boy in my class keeps asking me to flirt with him over text. Asking me if I still like him (cause I used to), but also in the past he has asked me to meet him outside class to touch and as he says “flirt dirty” hes been texting me asking for me to flirt with him as that would impress him he says but hes starting to freak me out i’m just really worried when I go back to school he’ll keep asking me and even start touching me, because he has asked to meet me outside toilets in school to hug and to touch my backside, this boy’s renowned for this sort of thing, and it’s not the first time he’s said this to me. i’m just really paranoid about this situation as he is in my class. I have heard about a similar situation in the year above me and the vice principal (head of pastoral care) had to ring social services about it. Will my teacher understand this situation? one of my best friends says she’ll take me up to him but I’m a little embarrassed will he mind if I say that. Please I don’t know how he will react..I have taken his advice and tried to deal with it but it’s not working, will he mind? Any ideas thanks