Yep. Infection indeed.
Wash it with hydrogen peroxide, not pure, but 1/10. One part of hp in 10 parts of water. Use the cover cup of the hp bottle to measure parts. 1 is to 10. It will be painful, expect that, but it won't kill you. And it will bubble as it will kill bacteria. Do this to clean the spot regularly and never forget to wear loose clothes. Don't wear anything that could tighten around the area of your navel, it will make the condition worse. If nothing is improved after 48 hours of a 4-hour cleaning routine using the solution, maybe it's time you go see a doctor.
Also, avoid using soaps or anything with strong or a lot of chemical ingredients on the area. It will infect more.
Good luck and get well soon.