more exercise = more stretch marks??

Hi all,

I can't be absolutely sure, as I've always had a few stretch marks near the top of my thighs but it seems now I'm doing more regular exercise (I walk to work most days - 1 hr long walk at about 4mph) there seem to be a lot more stretch marks all over the top of my thighs....is this right? Is there a way of minimising them? Has anyone else had this?? I'm glad I'm getting fitter but I don;t want to be too embarrassed to get my legs out when I finally feel like putting on a bikini again!

Thanks :flowerforyou: