Stretch marks, if you had them during pregnancy, won’t disappear altogether, but do fade over time to a rather festive silvery colour. Stretch marks are caused by a breakdown or loss of elastin and collagen fibres in the skin (often through rapid growth) which shows through to the top layer of your skin.
Whether or not you get them is largely determined by genetics and the speed and amount of weight you gain. There are all sorts of lotions and potions you can cover them with, and although there is as yet no scientific evidence to absolutely prove their helpfulness, many women swear by their favourite cream or oil. At least you’ll be doing something nice for yourself by taking the time to rub cream in, so by all means go ahead.
A friend suggested to me that they’re “a badge of motherhood”. Hmm, a bit cheesy for sure, but now when I see mine I remind myself of the amazing things my body is capable of like growing and nourishing a baby from scratch, rather than obsessing because I no longer have the body of a 20 year old (ahem, who am I kidding, I didn’t even have one of those before getting pregnant!)