I have a rash that started out like a ringworm but seems to be spreading and itches worse when i'm sweating?

Skin rash : It could be fungal infection like pityriasis , psoriasis or eczema . You can repost the question with a picture or see your GP .

Dermatophytosis: This probably is a dermatophytosis, but not a typical "ringworm." A quick exam under a Wood.s lamp at your PCP's office should help confirm, though a microscopic exam of scrapings from the affected area(s) might be required. Easy peasy and painless. Good luck & good health!

Picture and : Detailed description will be helpful. Infectious type rash may explain the spread. Washing hand with soap and water may reduce spread. Seeing a provider for evaluation will be wise