Scar Removal After Surgical Lipoma Removal?

My lipoma was surgically removed recently by a surgeon in the hospital it has left me with large incision that was stitched with 12 stitches. I will have the stitches removed in 2 weeks. It is a large cut from my right side next to right breast across the ribs till the back. I have been in a lot of pain since the surgery. I am wondering how soon can I start applying scar removal creams to the scarred area of my body and what is the best cream available right now to reduce the scar visibility? Is it normal to still be in such pain despite that my doctor gave me codeine pills mixed with Atasol. I have to take them every 4 to 5 hours for the pain but I still feel the pain even after I took the pills what can I do?