TretinoinKeratolytic AgentsLentigoAcne VulgarisOintmentsAdministration, TopicalSkin AgingCosmeticsChemexfoliationDermatologic AgentsHyperpigmentationAcitretinMelanosisNicotinic AcidsEmollientsTrichloroacetic AcidKeratosis, ActinicSkin CareFacial InjuriesCarcinoma, Basal CellRetinoidsSkinAdministration, CutaneousSkin PigmentationDrug CombinationsPersonnel TurnoverDouble-Blind MethodAntineoplastic AgentsTreatment OutcomeKineticsBone RemodelingBone and BonesHalf-Life