Lower Body Strength

Using only dumbbells and the strength workout videos, will there be a drastic change in my lower body? My legs seem to be getting toned and I can see the difference, but I feel like my bum isn't getting any bigger.

maybe i'm doing something wrong but I just feel like the muscle isn't building up enough for it to be a big change. has anyone noticed a massive change in that area or does anyone use gym machines alongside these videos?