Spiritually, an injury or scar may suggest that something negative and harmful has occurred, which is an external force rather than internal. We may not have dealt with it as well as we might.
Psychological / emotional perspective: It will often be significant which area of the body is harmed in the dream.
The nervous system can develop ways of giving information without us being conscious of it. This may give some indication of the area of life that is affected by the trauma.
To have an arm broken, for instance, might suggest that our ability to hold on is compromised.
If we see someone else who has been hurt or scarred we have probably been the ones who have hurt others in the past.
If this is so, there are various techniques we can use in the waking state to help us release others from the hurt we have inflicted.
The healing that subsequently takes place may then be recorded in further dreams by the loss of the scar.
Material aspects: An injury will suggest a recent hurt, whereas a scar in a dream suggests that there are old hurts, which have not been fully dealt with. These may be mental and emotional as much as physical, and can remain unnoticed until we are reminded of them. Just as in physical injury there can be many kinds of scars, so there can also be in the other areas. We may, for instance, be left with a pattern of behaviour which is irritating to other people, but without the clear connection given by the dream image, we are unable to understand it.