I Have Non Tender, Non Pruritic Red Raised Marks On

I have non tender, non pruritic red raised marks on the back of my thighs/lower gluts. They can be pustules, but I'm not sure if they all are. They seem to have a lighter-skin coloured halo around them when they first appear. They come in groups of 5 or 6, and it appears as though they come in a linear fashion (but again I'm not sure). I've been told molluscum contagiosum ... but its been ongoing for a year now. I was told folliculitis and put on probiotics - no resolution. Any diagnosis/advice?