In my practice, I recommend a fractional ablative laser for stretch mark removal. The procedure tightens stretch marks and improves texture. Multiple treatments are required and not all skin types may qualify.
If they are stretch marks (and I dont see a picture to know), there are no easy solutions. Strtch marks occur when the skin is stretched beyond its capacity to snap back. The only thing that can be done is to reomve the skin which may not be a good idea in the calf area. See you plastic surgeon and have a examination performed.