Help! Stretch marks, going on holiday and dont know what to do!?

Heyy, well first of all, im a 15 year old girl. I am not overweight, however I have recently (2 months ago) started to get stretch marks behind my knees and on my hips. The reason why I am worried is because I am going on holiday with my friend to greece in July, so i'll have to wear shorts. I have started using cocoa butter on them and also i have been leaving it on overnight (not rubbing it in). will that help at all? and also how can i maybe disguise them? Thank You :D