Stretch mark cyst?

question! so, a few weeks ago i found a spot on my inner thigh that hurt when i touched it. it was just a tiny little spot, i didnt think much of it. But today in the shower i felt pain there again so I went to feel it and it's now a little bump. Thinking it was a cyst, i felt around to see if it felt like a bubble underneath. It did, so I think it may be a cyst, but it's in my stretch marks on my inner thigh - is this a cyst? Why has it gotten worse over the past few weeks?