Swollen sensitive tip of foreskin appeared today. Need advice. Thanks

Hi there, went home yesterday and noticed my foreskin was quiet swollen, I applied ice to it. Went to sleep and now home again after work and I have noticed that my foreskin now has 6 tiny spots on the top. And I mean very small. My partner and I have been monogamous for three years now and we have had no other sexual contact. I have been swimming daily recently and have also used another person's swim togs. I do not always dry off completely. Could this be an sti like my worst fear or just a rash?

Hi Luka
Would you be able to see someone from a GUM clinic?
It is free also a picture can help sometimes