If you haven't already done so, please try exiting the application and restarting it.
Uninstalling and reinstalling the font (i.e., removing it from your Fonts, then installing it again) may also help.
If neither of those works, you can try:
Uninstalling and reinstalling the misbehaving font usually works best on Mac, but if after that the font is still not displaying properly, you may need to clear the font cache:
1. Close all applications.
2. Launch Terminal
3. Enter the following command at the prompt and press Return:
atsutil databases -removeUser
(You can also, optionally, clear the system font cache by typing
sudo atsutil databases -remove
for the first command, followed by the second two commands. Note that this will require you to enter your password.)
(You may also want to repair permissions, as well.)
4. Restart your computer
(To restart the font server without restarting your computer, use:
sudo atsutil server -shutdown then sudo atsutil server -ping)
Please also note that third-party font management software can sometimes cause issues with fonts appearing properly. If this is the case, try uninstalling/reinstalling the font using the system font management tool, i.e., Font Book on Mac.
If you're using Linux, you need to clear the font cache after installing a font (something like sudo fc-cache -f -v). You may also need to restart the font server lease see your particular system documentation on just how to do that. (It's generally along the lines of: /etc/rc.d/init.d/xfs restart)