The rash most often results from the entrapment of moisture between the silicone and the skin. During warmer weather or physical exertion, the skin sweats. The moisture on your leg cannot evaporate due to the presence of the silicone, thus becoming trapped.
Treatment is symptomatic - cooling and drying the area - avoiding conditions that induce sweating are the best approach. Over-the-counter corticosteroid lotions can be used. However, changes in the environment (cool/dry air) and lighter clothing are often more effective.
To help prevent the rash from occurring, make sure the skin is clean and dry before donning the stockings. It is also important to wash the stockings after each wearing to remove any skin oils and cells that collect on the stocking and band.
If the rash continues, discontinue wearing stockings with a silicone band until the warm humid weather changes. You should consult with your doctor if you have drainage from the rash or the rash persists.