I touched my palm to his mutilated cheek, and tried to stem my instinctive revulsion.
( I ( ( ( ( ( ( touched ( my palm ) ) ( to ( his ( mutilated cheek ) ) ) ) , ) and ) ( tried ( to ( stem ( my ( instinctive revulsion ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VP (VBD touched) (NP (PRP$ my) (NN palm)) (PP (TO to) (NP (PRP$ his) (JJ mutilated) (NN cheek)))) (, ,) (CC and) (VP (VBD tried) (S (VP (TO to) (VP (VB stem) (NP (PRP$ my) (JJ instinctive) (NN revulsion))))))) (. .)))
You could see where the bear had scratched across his cheek. 
( You ( ( could ( see ( where ( ( the bear ) ( had ( scratched ( across ( his cheek ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP You)) (VP (MD could) (VP (VB see) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NN bear)) (VP (VBD had) (VP (VBN scratched) (PP (IN across) (NP (PRP$ his) (NN cheek))))))))) (. .)))