Hi, I'm only 16 and I have tons of stretch marks all over my butt and it seems that more are surfacing as time passes but the thing is...

1. I only gained around 3-4 kg last year during the Nov and Dec and has since been maintaining this weight of 42kg.
2. I haven't grown any taller.
3. I have started using body lotion.

And now, even as I gain or lose weight, they're like only.. 100/200 grams? Is there something wrong with me? I am really skinny and has always been fit without any major weight gain or loss. But, the stretch marks seem to be increasing! It's really distressing! I can't wear anymore short shorts because they are getting on the top front of my thighs and slightly below my waist! I already have plenty on my butt! Is there anything wrong with me and what else can I do to stop them? Please help! :'(

DON'T PANIC!
You say you're only 16, and because you say you haven't had any major weight gain this is the only reason I can think of. Although you won't be actually gaining or losing weight, you're body will be changing shape as you grow from a child body to an adult. Your hips will get wider, chest bigger and your butt and thighs will probably widen a bit too, which is probably why you're getting the stretch marks. When they first form, stretch marks can tend to look very red and angry, but trust me (from personal experience!) over time they fade, first to a pale pink and then to silver and sometimes they disappear altogether.
Unfortunately, there isn't a quick fix 'cure' for stretch marks, some extreme cases can be lasered to make them paler, but I doubt you'd be able to get that done for another few years as chances are your body is still changing so they wouldn't be happy lasering off marks that would most likely come back or change on their own.
Something that can help is a product I used and still use sometimes now is called BioOil. It's a bottle of body oil that has a white lid and is orange in colour, and although it's quite expensive (£12.99 for a 100ml bottle) you only need a few drops for each application as it spreads really well.
If you visit your doctor they may have some similar products that could be helpful too.
But the main thing is to not be embarrassed by them, as I can promise you that everyone, all of your friends, will have at least one stretch mark somewhere on their body. So please don't worry about it!
Hope this has helped and good luck.

Try rubbing cocca butter it will reduce the appearance