First of all, your friend had better not have a scar constitution. If so, there is nothing you can do. If not, we should pay attention to the following aspects:

1. Go to a regular hospital for debridement and don't leave any foreign bodies.

2. It is best to use a very thin needle and thread for intradermal suture.

3. Prevent infection.

especially article 2 is very important.

Sure enough, everything is well done, so it is estimated that your friend will not leave a big scar.