▁p im ples . ▁The ▁o ily - sk in ▁type ▁is ▁not ▁necessarily ▁bad , ▁since ▁such ▁skin ▁is ▁less ▁pr one ▁to ▁wr ink ling , ▁or ▁other ▁signs ▁of ▁ag ing , ▁because ▁the ▁oil ▁helps ▁to ▁keep ▁needed ▁mo ist ure ▁locked ▁into ▁the ▁e pid erm is ▁( outer most ▁layer ▁of ▁skin ). ▁ ▁The ▁negative ▁aspect ▁of ▁the ▁o ily - sk in ▁type ▁is ▁that ▁o ily ▁complex ions ▁are ▁especially ▁sus cept ible ▁to ▁c log ged ▁por es , ▁black head s , ▁and ▁bu il dup ▁of ▁dead ▁skin ▁cells ▁on ▁the ▁surface ▁of ▁the ▁skin . ▁O ily ▁skin ▁can ▁be ▁s allow ▁and ▁rough ▁in ▁texture ▁and ▁tends ▁to ▁have ▁large , ▁clearly ▁visible ▁por es ▁everywhere , ▁except ▁around ▁the ▁eyes ▁and ▁neck . ▁ ▁P erme ability ▁ ▁Human ▁skin ▁has ▁a ▁low ▁per me ability ; ▁that ▁is , ▁most ▁foreign ▁subst ances ▁are ▁unable ▁to ▁pen et rate ▁and ▁diff use ▁through ▁the ▁skin . ▁Sk in ' s ▁outer most ▁layer , ▁the ▁str atum ▁cor neum , ▁is ▁an ▁effective ▁bar rier ▁to ▁most ▁in organ ic ▁n anos ized ▁particles . ▁This ▁protect s ▁the ▁body ▁from ▁external ▁particles ▁such ▁as ▁to x ins ▁by ▁not ▁allowing ▁them ▁to ▁come ▁into ▁contact ▁with ▁internal ▁t issues . ▁However , ▁in ▁some ▁cases ▁it ▁is ▁des irable ▁to ▁allow ▁particles ▁entry ▁to ▁the ▁body ▁through ▁the ▁skin . ▁Pot ential ▁medical ▁applications ▁of ▁such