My son fell off his bike a week ago. The handlebars hit him in the llq area of his abdomen causing a bruise. The area now feels lumpy a rope like?

Abdominal Injury. Make a trip to his pediatrician's office for a thorough abdominal exam including urinanalysis. It can be a abdominal wall hematoma or ..... Can be of intestine, the spleen is in left upper quadrant, left kidney in mid left abdomen and the colon is on whole left side. May be nothing, but.... You don't want to miss something/anything, right?
Healing tissue. Not too surprising -- following the initial bleeding or bruising injury - as the body's wound healing process occurs - will see changes in bruise color, decreasing overall swelling and some fibrous changes in the deeper tissue. If area is hot, red and tender recommend seeing your physician.