Rib healing: No real good studies on rib fractures. They can hurt for weeks or longer depending on how bad the fractures are. Usually walking around is good.
Subcutaneous tissue. The subcutaneous tissue, also called the subcutis, hypodermis, hypoderm, subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates.
Subcutaneous, as opposed to intravenous, injection of recreational drugs is referred to as  skin popping . Subcutaneous administration may be abbreviated as SC, SQ, sub-cu, sub-Q, SubQ, or subcut. Subcut is the preferred abbreviation for patient safety. Subcutaneous tissue has few blood vessels and so drugs injected here are for slow, sustained rates of absorption.