About two weeks ago I fell down the steps. I have very padded steps and even though it hurt, it wasnt that bad. I had a bruise on my behind but it wasnt that bad, although my butt cheek was swollen. Its been almost two weeks and the bruise is massive and had spread across my whole right butt cheek and almost to my hip. The bruise had grown 5x its orginal size. Is this normal or am i bleeding internally?
It is not uncommon for hematomas (bruises) to continue to enlarge for several days after an injury. In some cases, the injury to the soft tissues is fairly deep in the muscles and the bruising may not actually show up on the skin until several days after the injury. Once it starts to show up, it may then expand for several more days.
It will travel in directions by the pull of gravity. So, if you are reclining mostly, it will stay in the buttocks. If you were standing the majority of the time, the bruise could even travel down the back of the thigh and down the leg. If you were reclining with the legs way up and the head down, the bruise could travel up the back.
As to bleeding internally, technically, yes you are, since there is no blood on the outside (external bleeding). But, when you mention "internal bleeding" to a physician, that is usually taken to mean bleeding inside the abdominal, pelvic, or thoracic cavities. This internal bleeding usually signifies damage to the internal organs and is an emergency situation. This is not your case.
You most likely have damaged some of the small peripheral blood vessels, which supply the muscles and subcutaneous tissues. This then causes the blood to leak into the surrounding soft tissues. Since the skin is water tight, it holds the blood inside. So, technically, you could call this internal bleeding, but it is usually just called a hematoma.
The body will begin to resorb the hematoma as soon as it forms. The blood coagulates and the body begins to break down the blood cells. It then picks up the cellular debris and moves it back into the blood stream for elimination or reuse. This is why a bruise goes through all of the "pretty" colors as it goes away.
You can sometimes get the hematoma to go away a little quicker by using some heating pads. In the beginning, right after the injury, you would want to have used ice, to try to prevent some of the bleeding. But, now that the hematoma has stabilized and you are wanting the body to resorb it, heat is probably the best. Heat will increase the blood supply to the area, helping to pick up and carry away the cellular debris.
Do not leave the heat on for more than 30 minutes at a time. Longer than that, the body will habituate to the heat and will decrease the amount of blood flow to the area. You can put the heat back on again in thirty minutes if you wish.
So, yes, it is not uncommon for large hematomas to expand for several days after an injury.
Hopefully, this will go away in a little while, but it is going to take some time. While it is resolving, be sure to gently stretch the muscles in the area of the injury. Do not over do it, but you do need to gently stretch. If not, with large hematoma, the underlying muscle damage can cause scar tissue, which can decrease range of motion and strength. It is not too much of a problem in the gluteal muscles (the buttocks muscles), as it would be in the quads or hamstrings. But, they should still be stretched to prevent scarring.