hello, i recently purged my computer of most of my fonts and now this happens when i open up indesign - the interface fonts for adjusting values, sizes, etc. is some kind of font that I have a hard time reading. any way to change it back?
You probably removed fonts from System > Library > Fonts. That is NOT a good idea, and cause problems of the kind you encountered. The fonts should be restored which could be done by reinstalling your Mac operating system.
Also if you want to slim down on the fonts installled on your system a program like Font Explorer X Pro is a great choice that allows you to keep all your fonts but not installed unless a program asks for it then FXP will activate it.