Hey Adamas,
I suffer from this affliction in a chronic manner. I have ever since I was a kid, sometimes the spots even turn into boils that leave scars after (gross, I know). For the most part I have keratosis pilaris (chicken skin) on my thighs, butt, and arms - some of the bumps turn red and angry, especially on my bum after I've been wearing something tight.
If this continues to be an issue for you I'd like to highly suggest using a lotion formulated with 10% glycolic acid (or more). It keeps your skin very clear and makes it feel as smooth as silk. I use the lotion on my bottom, arms and thighs and it's the only thing that keeps the spots at bay for me.
As for your clients noticing, I'd try not to worry about it too much. Honestly. I've done many rearview activities in harsh, bright lighting while suffering from spots on my bum and no one has ever said anything about it - I think people are generally more interested in the shape of your bum than anything else.
Good luck!