You need to be seen somewhat urgently. By your primary care doctor if they can see you very soon (as in within a few hours) otherwise you should be seen in the ER because this may be a cellulitis. The ER would be your best option, though if you feel you wish to see your primary care doctor instead and you can get in very promptly that is a second best option. Cellulitis is an infection that can spread very rapidly and thus make recovery more difficult.
Another possible cause would be gout or pseudogout (deposition of crystals in the joints space)
And this can only be treated by your primary care doctor or by an emergency department physician.
Either way, this needs evaluation today so you can begin recovery with medication/antibiotics.
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