Pip can be a bit frustrating at times, especially if you've got multiple versions of python installed on your machine. When I run into this problem, what I typically do is check that pip has it installed but speciically within the instance I'm running. A quick way to do this is by running pip list within the instance! Open up an instance of python and run something akin to:
import os
print(os.system("pip list"))
If the module still appears in that list but refuses to be found when importing, then something else has gone awry - potentially the name used when pip installing is not the same that is used when importing in python, but that would be a question for the documentation.
If it does not appear in the list, then pip is installing to the wrong version of python! what you might need to do in this case is reassign which python instance is being considered default in your environmental paths. Open up an instance of your python and run:
import sys
print(sys.executable)
and it'll show you where your python instance says it's running the .exe from, and you'll need to set the folder containing that .exe in your environmental variables as your global path to python. More information on how to do that can be found here: How to add to the PYTHONPATH in Windows, so it finds my modules/packages?