To dream that you have been slapped implies that you should be more cautious. Someone has deceived you and you feel as if your value isn't being recognized.
To dream that you slap someone indicates that you have strong emotions of ire and wrath that you aren't expressing.
To dream that you have a rash suggests repressed negative emotions such as anger, disappointment, annoyance, and frustration. You may be keeping these negative feelings to yourself instead of properly communicating these issues with concerned persons.
To dream of a roast symbolizes depression brought about by a betrayal or a secret. This may also relate to worries surrounding your domestic life.
To dream that you have a blister implies that you are wasting your efforts on a rather insignificant matter. Pay attention to how the blister formed. To dream that you got the blister from manual and hard labor means that you aren't trying hard enough to resolve minor issues. To dream that you got the blister from a burn indicates that you are experiencing trouble in a relationship.
Notice where the blister appears. If the blister is on your hand, then it implies that you are struggling with control and authority. If the blister is on your face, then it means that you are experiencing problems with how you view yourself. Perhaps you are feeling inferior or unaccepted.