Is there anything I can do?
Over Pruned Kwanza Cherry
Certified GKH Gardening Expert
All pruning of your tree should be done after blooming.
Pruning to control size and shape is best done by removing any branches that stick up or out. Aim for pruning it's shape into a wide sweeping and weeping form.
Make sure you have not left stubs of branches, but prune back to the trunk so these wounds can heal.
Here is a link to refresh you on the care requirements.