Like, if you get in a fender bender and there is some scraped paint, you would say "the damage was..."
Such damage is sometimes referred to as "cosmetic". Oxforddictionaries.com defines this sense of the word as "affecting only the appearance of something rather than its substance".
Superficial is the word you're looking for.
: concerned only with what is obvious or apparent : not thorough or complete
: affecting only the outer part or surface of something : not deep or serious
"the damage was superficial"
I've heard this called, just a flesh wound. See also: but a scratch.
From the source:
King Arthur: [after Arthur's cut off both of the Black Knight's arms] Look, you stupid bastard, you've got no arms left!
Black Knight: Yes I have.
King Arthur: Look!
Black Knight: It's just a flesh wound.
It's a blemish:
- A small mark that makes the appearance of something less attractive.
- An imperfection that mars or impairs; a flaw.
In the Black Knight sequence in Monty Python's Holy Grail, King Arthur and the Black Knight fight until Arthur cuts off Black Knight's left arm, to the following dialogue:
King Arthur: Now, stand aside, worthy adversary!
Black Knight: 'Tis but a scratch!
So, "the damage was but/just a scratch".