I had been using a Dynafont "KYOKASHO-W4" font without any problems, but this morning Photoshop would not let me use this and kept switching either to the Dyanfont KYOKASO-W3 font, or another Japanese font (a gothic Japanese font). I just installed Acrobat Pro the day before. Post hoc ergo propter hoc? Clearly something was corrupted. I have re-installed the fonts, uninstalled and re-installed Photoshop CS6, and uninstalled Acrobat. I need this font for the book I am writing which is a pictorial guide to Kanji, and evrything I have done do date has been in the above-mentioned font. This particular is one that is recommended by the Japanese Ministry of Science, Education, etc.
It does sound like something new (Acrobat would be a possible candidate) has messed things up.
On a PC, I would see if you have a System Restore Point, from before that installation. First, create a new System Restore Point for today, then boot to Safe Mode, and choose System Restore, choosing one of those older System Restore Points. Test. At worst, you have lost a few minutes, as you did the System Restore Point for today.
On a Mac, I think the similar function is Time Machine (?), but do not have any idea how that works.
Good luck, and hope you get your font back.