There's a lot of answers I can give,but perhaps it's best to download the installer so that it's there when you need it.
http://prodesigntools.com/tag/ddl Photoshop CC Mac will be there.
Please pay careful attention to the download instructions.
Then put the installer in a safe place.
Great! Thanks for the link.
Just out of curiosity, and no need to go into lots of detail, what would be your best guess as to where it went?
If you uninstalled and the CC app won't let you reinstall because it thinks it is still there, try to sign out of CC and then back in. If that doesn't work you need to run the CC Cleaner Tool.
As it happens there was a similar case a few days ago. Downloaded and installed, but nowhere to be found in Applications. But that doesn't mean it's not there - what you should do is go look for the actual program files (I don't know where they are on Mac). Then make a new shortcut or alias or whatever it's called in the Mac world. On Windows there will be an .exe file that launches the program, and I assume some Mac equivalent will be there.
Of course if you're a purist (like me), you'd want to uninstall and try again in case the download is corrupt. Or the missing shortcut could be a minor bug.