This element is labelled L3, suggesting that it's an inductor. It's OK for it to be black and have a slightly non-uniform color. If you can reach the pads with a multimeter, you could check that it conducts in both directions, with a typical resistance in Ohms or tens of Ohms. Of course, testing an element in-circuit can give false results, but getting such a small part off the board for inspection is difficult and risky.
If you want to diagnose your RPi, I would start by measuring the voltage on 3.3V pins. If you don't see the right voltage, your board may have an issue with the overcurrent protection or the voltage regulator, which could theoretically be fixed.