Error in editing code for Appointments +

I am getting this error when I try to edit the code/css for the Appointments + plugin.

Fatal error: Allowed memory size of 94371840 bytes exhausted (tried to allocate 1048576 bytes) in /home/bapwichita/wichitabap.org/wp-admin/includes/misc.php on line 284

Any ideas on how to fix this? If I uninstall this plugin and reinstall, will I lose my appointments and data already created?

Thanks!