What should I do?!

Guys I just need some advice I’ve been with my boyfriend for around 6 months now. We’ve moved quite fast in our relationship no we’re not talking babies and marriage any time soon but we’re very ‘loved’ up, I love him and I’m sure he loves me. Before him I was with another guy who I thought was serious about me but it turns out he had a few of us on the go at the same time. I found out and left him and shortly after that I met my current boyfriend. Anyway last night I went out for food with my best friend and my ex came in. My best friend called him over I honestly don’t know why she did it and I’m so angry at her for it but I didn’t want to cause a scene. He came over and slid in the booth next to me, I was against the wall so I had no way of getting away from him. He was flirting with me and asked me if I still loved him but I told him I wasn’t interested and I’m happy with my man. He ran his fingers through my hair, I pulled away but there wasn’t really anywhere I could go. Afterwards I went home and waited for my man to come back. I was doing some work so wasn’t paying much attention to anything else when he came in, he didn’t say anything but he came over and started gripping my hair. Not like angrily like pulling just like he was scraping it up I assumed he was just playing with it so didn’t acknowledge anything but then something caught my eye in the reflection and he was holding a pair of scissors to my hair 😭😭😭I was petrified! He was just staring at me in the mirror with no expression holding it so tight I couldn’t move my head away. I asked what he was doing trying not to cry and after a few moments he released his grip and laughed! Then he said something along the lines of if he finds out any man touches anything of ‘his’ again he’ll cut it off. 😭😭😭but then he continued like nothing happened and I was so shocked and scared I didn’t know what to do! He’s never done anything like this before I don’t know who told him about my ex touching my hair but I don’t know what to do! I couldn’t sleep last night he’s acting like everything is normal but he really scared me! It was his expression I felt like I saw something evil I know it sounds crazy! Usually I would speak my mind and confront him about my feelings but he’s really scared me. I love him so much but I really don’t know what to do am I over reacting?

He’s never threatened me before but he has got violent with 2 guys in the past for being too friendly with me. I’m not sure if this time he’s blaming me cos it’s my ex but either way I feel really uneasy I’ve barely spoken to him today