Need more info
I will assume this is an injury to a child.
It would be unusual for it to bleed after 20 minutes of steady pressure. Most people hold pressure for a moment and then peek, hold pressure again for a minute and peek, etc. This is not 20 minutes of pressure! hold steady pressure for 10 minutes without peeking! if fat is showing or the bleeding does not stop, a stitch or two or glue may be needed.