Weight gain immediately after surgery (TT Revision)

Had TT revision today. I actually feel great but was wondering about why I weighed 5 pounds more this evening then before I went in this morning for the revision. I haven't eaten anything all day except a cup of coffee after surgery and a half of a plain turkey burger no bun, no condiments, or anything this evening. When I had originally TT, I came out a couple pounds lighter so i was surprised i am HEAVIER after the revision. which was just some "thinning " at the incision line.

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