What Causes Large Discoloured Patches On Inner Thighs?

circular discoloration on inner thigh both sides not raised not rough no itch smaller circles forming around fifty cent sized thigh discoloration. half circle discoloration on my rib cage Is this something i need to worry about I am 49 menopausal woman having hot flashes day and night sweats if i wear my swimsuit you can see these large discolored spots what can i do?