It's rarely a biggy tbh, use a bit of soap solution to see if it actually needs repairing. To fix it you can get a new gasket from pug for pennies, bit of a pig to get in though, so probably only worth it if you're sure it's a problem or if you're really anal about how your engine bay looks.
![Wink Wink](https://www.306oc.co.uk/forum/images/smilies/wink.png)