Cyst with septations

hello 1 year ago i had 4 dermoid cysts removed from the inside of my left ovary. the ovary was saved but deformed and closer to my fallopion tubes ive recently been getting the same pain a dull pain but now more frequent sharp pain. i have had a ultra sound and have been told i have another cyst again on the left side they also have said it has internal septations , does anyone know what this means ? i cant seem to find much online , im back at the hospital on the 1st july for further management