Roll20 isn't a paint program so you cannot erase a portion of your stamped objects, it also cannot apply curves to things already on the tabletop. What you can do is cover up part of the road section you have with other objects, like trees or shrubs or even a curved section of grass texture. If you have access to a paint program like gimp or photoshop you can make a masking overlay that is transparent for the curved section of the road you want and a background texture for the rest. The easiest thing would be to cover what you had already down. For my own maps I put them together outside of Roll20 and save them as a .jpg to a size less than 5mb and add additional elements in the game. It saves on processing power. Happy rolling Ed
