What kind of tablet are running Photoshop Touch on?
Have you tried to force quit+ restart PS Touch?
Follow these steps to force PS Touch
1. Tap and hold on the PS Touch app icon
2. When it starts to jiggle, tap the http://18.104.22.168/bmi/km.support.apple.com/library/APPLE/APPLECARE_ALLGEOS/HT5137/HT5137--mi nus-001-en.png to close it.
3. Double-click the Home button and try opening the app again.