In the first week apply the tea tree oil (if necessary (i.e. if it burns hard) slightly diluted with water) to the keloid in the morning and evening with a cotton swab.
After about two hours, wipe off the residue with a cotton swab soaked in water. (In the evening it can act throughout the night)
The tea tree oil dries out the skin, the dry skin should be gently removed with a wet cotton swab. So the keloid slowly disappears.
Take a break for the second week.
If it doesn't improve after that, the process is repeated.