In most cases, the condition is mild and if the vesicles are clear, no medications are needed. However, in the case of red sweat rash, more measures are taken including preventing sweating as much as possible by avoiding excessive exertion in humid climates, air conditioning and avoiding any tight clothes or replacing them with one made of cotton or linen to absorb the produced sweat and prevent clogging.
Medications may be used for such conditions in case of infection and to relieve the irritation. They include calamine or boric acid as well as topical antibiotics in case of infection. If your condition is more severe, your dermatologist may advise using retinoids. Those drugs act to reform your sweat ducts and prevent their clogging, and are chiefly used for severe acne.
They should never be used as a self-medication due to severe side effects like hepatitis and alterations on your cholesterol balance.