Anytime you have a skin problem that doesn’t go away, you should make an appointment with your health care provider. Small lumps or cysts (fluid filled sacs under the skin) are common and most of the time aren’t dangerous. They can sometimes get infected and in very rare cases they can be something serious.
It is very difficult to tell the difference between things that are worrisome and things that aren’t without seeing your doctor. If the bump is painful, red, or growing/changing in any way, you should see you doctor right away. If the way it looks bothers you, often there are options to help with that as well.