Welcome to DoctorSpring.
You didnt mention what caused the deep cut. So i am assuming it was not much of contaminated or complicating injury. You say the wound started healing. Human body has a awesome reapir process, so if its already healing the best you can do is not to interpret the healing process.
1.Since its wond near your buttocks , make sure you are not contaminating the wound while using a toilet
2.Dont sit over it for long time
3. Sleep in a prone position
4. Apply a non occlusive sterile plain dressing.
Hope this will help