The Dust of 100 Dogs by A.S. King

In the late seventeenth century, famed teenage pirate Emer Morrisey was on the cusp of escaping the pirate life with her one true love and unfathomable riches when she was slain and cursed with "the dust of one hundred dogs," dooming her to one hundred lives as a dog before returning to a human body-with her memories intact.

Now she's a contemporary American teenager and all she needs is a shovel and a ride to Jamaica.