Evening primrose oil has not been shown to treat acne and is not approved to do so. Anecdotal evidence from an extremely small, unrandomized sample on the internet will lend you no benefit. Consider seeing a doctor for acne treatment if is bothering you or interfering with your wellbeing.
My teen daughter gets keratosis pillars ( pimple like eruptions on the backs of her upper arms) and pms pains unless she takes it. I've tried it but don't notice anything different for me since I don't have either of those problems. In general, I think they say it supports female functions, not sure if it does anything for men.
Not EPO but I started my 14.5 year old daughter on royal jelly (500 mg, 2x day) and her skin is really clearing for the first time ever.
I found that cutting out the small amount of dairy I was using (butter, heavy cream..) and caffeine did more for my skin than years of evening primrose.