Several weeks. It can take 2-6 weeks to completely heal. During part of this time it may be critical to maintain a certain head position, depending on the type of repair you have.
Depends on repair. Some retinal detachment repairs involving a gas bubble can take up to eight weeks to heal. Others can be fairly well-healed within a couple of weeks. For someone who is young like you the possibility of further problems exist later so follow up with your ophthalmologist over time is critical.