There a couple of things you can do--one is long-term, that is, there are products you can use which will, over time, reduce the visibility of the scar. Some of these products are: Mederma ( very effective, but expensive) Bio-Oil (somewhat slower, but moderately priced), and Palmer's Cocoa Butter Oil (it's the slowest, but also the least expensive). Then, there is the cosmetic approach--buy a foundation, preferably in cream form, which closely matches the color of the scar area. As well as some translucent finishing powder. Apply the foundation, smoothing around the edges until you have the scar well-camouflaged, then "set" the foundation with a dusting of the powder. There's also a product called "Covermark", which will cover scars, birthmarks, tattoos, and other marks anywhere. It's not cheap $25 for a jar, and you also need to buy a finishing powder, also $25--but there's a YouTube video which shows you just how effective it is. But, you know, there's a third option: learn to accept your scars as evidence that you are a survivor. It's what I have done: I'm a breast cancer survivor, and look at mine as honorable scars, taken in battle with a deadly enemy.
usually it depends where the scar is. but, you could try putting ointment/medicine on it and use make ups such as mineral foundations, bases, cream blushes, and really any type of skin colored matching facial cosmetic you can find somewhere. i once smashed my face into a wall and i got this gigantic scar on my face and i used a creme base and mineral foundation and i put medicines on it and it healed within a week.