means a sac filled with fluid.
and from what you have stated you seem to have a cyst n your lacrimal gland
it is not very rare and it is a benign condition of the lacrimal gland.
you need to make sure you dont let it get infected and maintain good hygiene.
it is advisable to visit an ophthalmologist and consult if you develop pain or redness
in the region.
you can also get it removed for cosmetic reasons.
please donot worry as it is mostly benign.
i hope i have answered your question
take care and wish you good health