Please do a search about stretch marks. You'll find many answers telling you that guys don't care about stretch marks. You don't need to worry about them. Only a virgin would be surprised to see stretch marks. In any case, he'll be too happy being with you naked to care about stretch marks. Again, you've got nothing to worry about.
Stretch marks where? I don't really care for overly obvious ones. If they're already faded, and or not too long, I guess you could say. Then they're not much of a bother. Unless there's marks, with excessive skin along with it.