Why does my fuchsia have deformed bloom?

More like seagull droppings or have you splashed it with patio cleaner, have they had green/blackfly?.
Remove the damaged pieces and let new growth come along. See if it is getting over the disfiguration.

could be a natural condition called fasciation. cells divide erractically, often due to insect damage or frosts. it is perfectly harmless so dont worry.

welcome to GoY too.

this sometimes happens with the firt flower or two of the season, sometimes due to insect damage as abov, and sometims due to a change of enviroment while the bud is forming. a sudden change of temperature for a day or two for example . usually no real damage is done and the susequent flowers are good