"grow young again," by 1879, from rejuvenescence, etc., or from Medieval Latin rejuvenescere "renew one's youthfulness."
Entries linking to rejuvenesce
rejuvenescence n.
"renewal of the appearance, powers, or feelings of youth," 1630s, from Latin rejuvenescere "become young again," from re- "again" (see re-) + juvenescere "become young," from juvenis "young" (see young (adj.); also see -ence).