This is the "A Doctor tending a Patient's Foot in his Surgery" painted in the Flemish tradition. The artist, David Teniers the Younger, was influenced by Adriaen Brouwer and made several variations of this composition. You can see how strongly reminiscent it is of Teniers' work, but unfortunately, the execution is too poor to be authentic.
Look closely at the details - the doctor's pose, the patient's expression, even the open-mouthed fish hanging from the ceiling might suggest a commentary on gullibility in quack doctors. This was a common theme in Flemish painting of the time, ridiculing those who claimed to have healing powers without any real expertise.
Interestingly, this composition has been copied by other artists after Teniers' death, and it's possible that all these versions were based on an original lost work. The signature at the bottom left is suspiciously weak, suggesting that it might be a false attribution.
A Doctor tending a Patient's Foot in his Surgery hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.