Was this only one app or more? If one app go to sttings to check, or try "inching" the display, thumb and finger and separate the distance between them to enlarge. Otherwise 1. Turn off and restart and check, 2. Empty app cache and restart (go to Settings, look for Apps, then finf the app in the list, open it, click on Storage, then clear cache. Then do a restart. 3. If still a problem but happens to all apps, go to Settings, use search tool to look for 'font' and 'screen zoom' Various responses will appear, look at 'font size and style' and play with those settings, etc.
