Exercising after BBL. Will I lose definition if I exercise too much?

Once you are fully healed from the BBL procedure, the transferred fat in your buttocks will act like the rest of your body. This means that losing weight with most likely decrease the size of your buttocks proportionately with the rest of your body and vice versa.

You can definitely exercise after a BBL. The only thing to keep in mind is
your weight. You can exercise, maintain and tone but what you don't want to do
is lose too much weight. If you lose over 5-10 pounds you may begin to see a
change on your gluteal size. As you lose weight you lose it
proportionally everywhere and yes your butt will get smaller. If you
gain weight your butt will get bigger. So just try to find the weight that
works best for you and workout to maintain it.

Best Wishes

Dr Miami :)