Sign on to the icloud http://www.icloud.com, then go to photos, then albums then recently deleted and IF you are lucky they will be in there and you can undelete them. It possible they are gone for good, BUT stuff does stay in recently deleted for a while. (It says up to 40 days but your milage may vary)
Here is a link to some other alternatives. But the easiest way will be if you have a backup of your phone. Good luck and hope you are able to recover them.