You can start gently stretching your calf muscle with the towel stretch right away. Make sure you feel only a gentle pull and not a sharp pain in your calf while you are doing the stretch.
Wearing a quarter to half-inch heel lift in each shoe might reduce your pain as you start to recover from your injury. You can purchase heel lifts at most pharmacies. You can stop using the heel lift when you have no pain while walking.
After you can do the towel stretch easily, you can start the standing calf stretch.
After a couple days of stretching, you can begin strengthening your calf and lower leg muscles using elastic tubing as described in the next exercise.
You may do the last 4 exercises when you can stand on your toes without pain.
You can challenge yourself by standing on just your injured leg as you do this exercise.
Another good exercise is hopping. You can start at one end of the room and try to hop as high as you can across the room on one foot. Jumping rope is also a good exercise.