when to use heat on strains and pulls
Heat can be applied to further relax the muscle when the swelling has lessened (in general, about 12-24 hours after the initial strain). However, the early application of heat can increase swelling and pain. Note: Ice or heat should not be applied to bare skin.
The only difference between using ice and heat is that 1 is better for you at a specific time in your healing cycle. Ice is used first, right when you get your injury, to decrease pain / swelling and inflammation. Heat comes later, to increase blood flow circulation and stimulate the body's healing response.