Okay kiddo, sometimes our bodies can get little bits of things stuck inside of it like splinters, dirt, or even pieces of surgical material if we've had an operation. When this happens, our body tries to get get rid of the little intruders by creating something called a foreign body granuloma.
Think of a foreign body granuloma like a little army of soldiers sent to protect against the intruder. The body sends special cells to the area where the foreign object is, and these cells surround the object and work together to try and get rid of it. They can form a little lump, and if it's under your skin, you can even see it and feel it!
It's like when you get a tiny splinter in your finger and your body makes the area around the splinter red, swollen and painful. It's not the splinter itself that's causing these symptoms, but your body's response to try and get rid of it.
Fortunately, most foreign body granulomas are harmless and usually go away on their own once the foreign object is removed or dissolved. But if you have one and it doesn't go away or gets bigger, it's important to see a doctor. They can help determine the best course of action to treat it.