If you lost the weight thru crush diet, fasting, etc.. it may not be lasting and healthy in long run. You will looks slimmer but may not be stronger and healthier.

It is better to achieve it via healthy lifestyles change, thru regular exercise (cardio / interval training / weight exercise) and balance diet. You gain stamina and strength that helps to improve your lifestyles beside looks better than a skinning bum.

Scars are mainly lose skins that could be improved by applying cocoa butter cream avail at most Watson / Guardian. Weight training to build some muscles is helpful to tone up.

Visit to Guardian or Watson, they have it at skin care products. It meant to reduce stretch mark for pregnant woman. Something like

The fastest way to gain weight healthy is to go for weight training and consume at least 20% ~ 30% surplus your daily maintenance calories.