After someone has had an injury to the skin, they’ll often get a bump or a bruise. Bumps and bruises may not appear straight away but the skin can still be painful and often feel tender or swollen at first. Bumps are swellings caused by fluid under the surface of the skin. Bruises are bluish or purple-coloured patches that appear because tiny blood vessels beneath the skin burst and leak blood into the soft tissue. As they heal, bruises usually change to a yellowish green colour.