retouch

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To add new details or touches to for correction or improvement.
• intransitive verb To improve or change (a photographic negative or print), as by adding details or removing flaws.
• intransitive verb To color (recent growth of hair) to match hair that was tinted, dyed, or bleached at an earlier date.
• intransitive verb Archaeology To modify (a flaked stone tool) by secondary flaking along the cutting edge.
• intransitive verb To give or make retouches.
• noun The act, process, or an instance of retouching.

from The Century Dictionary.

• To touch or touch up again; improve by new touches; revise; specifically, in the fine arts, to improve, as a painting, by new touches; go over a second time, as a work of art, in order to restore or strengthen a faded part, make additions, or remove blemishes, for its general improvement.
• noun A repeated touch; an additional touch given in revision; specifically, in the fine arts, additional work done on that which might previonsly have been regarded as finished.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Fine Arts) A partial reworking,as of a painting, a sculptor's clay model, or the like.
• transitive verb To touch again, or rework, in order to improve; to revise.
• transitive verb (Photog.) To correct or change, as a negative, by handwork.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To improve something (especially a photograph), by adding or correcting details, or by removing flaws.
• verb transitive To colour the roots of hair to match hair previously coloured.
• verb archaeology To modify a flint tool by making secondary flaking along the cutting edge.
• noun The act of retouching.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb give retouches to (hair)
• verb alter so as to produce a more desirable appearance