You are most likely suffering from Herpes Zoster. It has nothing to do with unprotected sex. Rashes can be due to some other reasons ae well. For now take pain killers, anti virals and PPI. If you are concerned about
HIV then get and tri dot test done but it will only reveal after 3 months of contracting the condition.
Next Steps
start on pain killers and anti virals
Health Tips
wear light cotton clothes