you have to rebuild from visual studio
2 ways:
open visual studio and then press CTRL+SHIFT+B and let it compile, the time it takes depends on your computer, plus if you have Unreal engine installed on your SSD it takes a lot less to compile.
another way is to just close unreal engine completely and run the build from Visual studio by pressing CTRL+F5.
Make sure you have live coding disable when you are compiling with the Visual studio.
Live Coding is not the best IDE out there, I wouldn’t get use to it too much, Personally I always have it disabled.
CTRL+SHIFT+B is the way to go if you have Unreal Engine downloaded from the epic launcher, if you have unreal engine from source code, then CTRL+SHIFT+B would take a lot of time, so in this case the best option is to close Unreal engine everytime you are making C++ changesand just run the build from Visual studio (CTRL+F5).
Hope this helps