Pinhole marks from Derma Rolling! (Photo)

I've been rolling weekly with a .5mm roller for 3 weeks. I noticed after my 3Rd time that I have pin prick marks all over my skin where I passed the roller. Is this just the micro-channels caused by the rolling or have I made my skin worse?? I'm so worried that I have caused more damage to my skin.The first session I went really lightly and have applied more pressure the last 2 sessions, but I didn't press overly hard. It'seems been an hour since I finished and the redness have mostly gone down now.