I can’t tell what caused this bump.
But I can tell you that having 11.6 mg/dl uric acid is a serious problem and that you ought to see a doctor about that. Excessive uric acid is the main cause of gout, not what you just ate. It would be helpful if you had older test results. If that is your first uric acid blood test, you would ideally do a second blood test and see a rheumatologist afterwards. You’d be able to show your bump to that specialist who may be able to make an educated guess as to what it is or suggest a technologically-assisted examination of the elbow and/or bump.
But if seeing a specialist quickly would not be possible in your situation, you should at least see a general doctor, show them this bump and ask firmly that they do something about your uric acid without delay (assuming the second test doesn’t come back much lower).
You’ll likely end up taking a drug called allopurinol because there’s little hope of addressing such a dangerous level of uric acid without strong medication. But it may be worth doing some tests to try to determine what causes this excess of uric acid in the bloodstream because you might possibly benefit from more sophisticated treatment than simply taking allopurinol.
In the meantime, it’s good that you’re drinking a lot water (but don’t overdo it!). You should ideally also avoid alcohol and make sure you eat lots of vegetables. This won’t be sufficient to solve your uric acid problem but it may help prevent kidney problems.
Not eating food very high in purines is also prudent but if you’re not used to a vegeatarian diet, take care to avoid nutritional deficiencies (if your body can handle lots of dairy, that’s the easiest way to be safe).
And as long as you don’t know why exercising your elbow is painful, I think it would be prudent to refrain from doing anything that hurts a lot.