Try this.
In device manager, right click on the microphone entry and uninstall it. Give it a few seconds to complete that. Once it's done right click on the header for "Audio inputs and outputs" and scan for hardware changes. Once it installs it, test the mic.
Alternatively, uninstall it as above, but then reboot the machine and see if it works on reboot.
Another thing that might work that I discovered by accident is this. Right click on the volume control in your taskbar and select recording devices. Once there, right click on the microphone in the list and select properties. Under the advanced tab there's a dropdown for default format. Change it to something different and hit apply. Test it. I've noticed that even changing this to something, applying it, and then changing it back to the same setting as before would still fix the problem.
Windows 10 routinely breaks my webcam microphone and makes me sound like Mickey Mouse according to my friends. Doing one of the above fixes it. It's a hassle to deal with and is my biggest problem with Windows 10. Not being able to manually control drivers for specific devices. Almost every reboot of my computer screws up my mic.