Cyst in baby's head and femur measuring small

Brittany

I am 26 weeks but I had a scan at 20 weeks that showed a cyst in my babies head (she actually called it a soft mark ) , and her femurs are small. Now I know it was still early , and she has alot more time to catch up but it still worries me . I did the quad screen and it all came back negative for everything. I am just really worried and concerned, the doctor said the cyst should go away by my next ultrasound. Has anyone else experienced this?