system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to the blood after you internally bleed?

Does it just stay there forever? Where does it go in the first place? Does it dry up? If so, how?
gpt
It does not stay there forever. Generally your body reabsorbs blood. 


Bruises are a good example. For larger quantities of blood you may need surgery to relieve or drain the blood from your body cavity or interstitial space. Draining this blood doesn't remove all of it, some of it will still be absorbed. 


It doesn't dry up, it clots. 


A very basical description of how it clots is because of a series of enzymes called prothrombin and thrombin. Prothrombin stimulates more thrombin and thrombin can stimulate clotting factors. Fibrin is basically a sticky protein that can form a mesh to collect platelets and then other blood cells into a single mass. 
Platelets and fibrin bind together to become as solid mass(or clot!). 


If you are more interested in the minutiae of the clotting process, look up the coagulation cascade. 

Macrophages are a type of white blood cell, they can digest other cells. This includes digesting blood that has spilled and clotted within your body. This is what happens to internal bleeding including why bruises fade over time.