Some minor swelling over the treated veins is normal post sclerotherapy but if you have significant swelling in the ankles, please see your physician as this may indicate an excessive reaction or underlining blood clot. Properly measured graduated compression stockings should help.
Most likely the indentations will not disappear following forehead vein removal but at least you will eliminate the veins. You have 2 choices---leave the veins alone with the indentations or treat the veins and see if the indentations resolve.