How does an RN get into being an nurse injector or Botox and such? Is there a licensing class?…recommendations?

Try to find a job in derm, even part-time if you can. That experience alone will be invaluable to you. Especially if they do clinical and cosmetic derm. I lucked out straight out of school and got hired in and let me tell you it was a learning curve.

There are nurse injector and botox classes available. Check the area you live in. Look for facilities that offer support after you have obtained certifications. Get as many hours as you can practicing the techniques.