What do you do when you really don't like a piece you have set out to learn?

Not liking and liking a lot are two aspects of the same thing. In music they are a reliable basis for what is sometimes thought of as interpretation. (I think it's more basic than that, but that's a long story.)

For starters, translate "I don't like it" as "I don't get it." Narrow down what it is you don't like: is it this note? that interval? Imagine that they are alive and that you, being in charge, can approach them so that they reveal themselves to you. Imagine they are dogs that look threatening and that you are intent on getting them to wag their tails.

The piece will take on what I think of as a plot line. You still might not really like it but you will probably, after this effort, be at least intrigued.