ok did u try the recovery mode if not try that thats my 1st option u can do hold down power and volume up button and release power button once u see apple logo and keep holding the volume up button until u see lock screen then remove what u install last from cydia.
2nd if cydia does work remove cydia substright and all sources that are not default with cydia.
3rd if the 2nd option does work try this reinstall cydia substright and preference loader then install icleaner pro to clean ur device then install tweaks.
and if none of theso about do not work i guess try restoring with simi restore if it works with 8.3 if not restore with itunes then rejailbreak.
more advance option you can check the logs see what is causing it there be more info on the error there sorta like debuging the app.