There is no indication found regarding any sort of injury or condition related to Adam Sandler's right ear lobe. If it's not a result of an injury, he was just born that way.
Of interest, most celebrities with physical deformities have no problem speaking about extra nipples, webbed feet and mismatched eyes. Check out RadarOnline.com's guide to interesting body oddities.
Speaking of ear, here are some tips that can be taken in consideration to avoid ear injuries from HealthGuidance.org.