The cruciate ligaments are found in the knee and they cross over each other, hence the name, from the Latin for 'cross'. The prvent the knee from overbending or overstraightening, amd limit how much the bones of the knee slide over each other.
Regarding your more specific questions: it depends on the type of injury and how extensive it is. You haven't mentioned if you are having any other form of treatment, such as physiotherapy. I suggest you ask your doctor about your concerns.