What are the stages of tissue healing?

It depends on the extent of the damage, sometimes the body can repair the damaged cells themselves in a process called resolution, or it can replace the dead cells with the same types of cells. This is called regeneration. Or, if the damage is more severe, it uses a process of fibrosis, where it replaces lost tissue with scar tissue.

Platelets and fibrinogen can be a part of this process if blood needs to be clotted to stop bleeding. This process forms a platelet plug, which in common terms is a scab.