Midwifery Head Katie replies:

Check with your GP that you don't have an infection. Symptoms include extreme soreness and the area might be leaking fluid. You might also be feeling a bit under the weather.
You may feel a ridge down the length of the area that was stitched. This is common and is often a cause of soreness.
What has happened is that the body has generated an excess of scar tissue and produced this haphazardly along the wound. It usually flattens in time, but you can help by gently massaging the line of the ridge. This may be easiest to do in the bath or the shower as the water lubricates your fingers.
Otherwise, you will need to use a little oil on your thumb and index finger. Put your thumb on the inside of the tear, inside the entrance to your vagina, and your index finger on the outside and gently stroke the ridge.
As soon as you become accustomed you will be able to rub a little more vigorously. This increases the blood supply to the area and promotes healing.