It's quite possible that both could be true. Eating disorders knock your digestive track out of wack..the prolapsed intestine would be caused by excess fecal pressure. That could be because she's not crapping regularly because she's not eating. Does she eat? Does she go to the bathroom after eating? Bulimics sometimes get puffy cheeks too. Either way, all you can really do is continue being there for her and watching for clues.
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"The time has come," the Walrus said, "To talk of many things:
Of shoes--and ships--and sealing-wax-- Of cabbages--and kings--
And why the sea is boiling hot-- And whether pigs have wings."