I'm treating a yeast infection 5 days now, with clotrimazole 2%. 2nd day irritation gone. 4Th day came back even worse. Side effect of clotrimazole?

No. The "yeast infection" may or may not have been present or the medication was ineffective if it was present. Have a MD re-examine you and confirm the presence of yeast or not and then go from there for a treatment plan.