Is your plant indoors or outdoors? It's usually a dryness problem when it's indoors. However, it's distressed wherever it is. Overwatering will do the same thing, but not as quickly.

Make sure the soil isn't dry and hard.

Has the root ball outgrown the pot?

How fresh is the soil mixture you have, it could be that there are no more nutrients in it and might need fertilization.

Sometimes, just for buds not opening, a gentle push up from the base will help it along.

You can always google "fuchsia" for more information.

good wishes!