Scars are permanent. While scars are permanent, there are different treatments that can help minimize, fade or hide surgical scars. Talk to a board-certified plastic surgeon to find out what your options are.
It depends. Most scars improve with time and some topical therapies (silicone, paper tape, etc). If they are still unsightly, scar resurfacing with dermabrasion or laser can be performed. However, if a scar is causing a webbing, it is excessively wide, or tethered to underlying tissue, it will often need a revision (cutting it out and sewing it back together).
To improve mature... Scars' appearance. Depending on your age, the mechanism of injury, and the location of the scar, it may take 6-18 months for a scar to mature (lose all its redness.) it may be possible to revise the scar at that time to make it less objectionable in appearance. Scars cannot be erased or removed, though.