I have naturally 3a hair that I had straightened so I permed it to avoid having to cut off all of the straight hair. In the past I have permed it from time to time even without the straightening issue. Here is what I discovered...

When I get a perm, it really doesn't make much difference after a while. At first, I have a lot of curl at the roots which almost never happens naturally and then my natural hair pattern comes through. Apparently my natural curl pattern is stronger than the perm. Even a very tight spiral becomes my natural pattern after about 3 weeks. What I do get from the perm is more definition to the curls and an easier time getting them to curl versus frizz.

I don't have an issue with straight hair at my nape, so I can't tell you what it will do in your hair. Good luck should you decide to try it.