Then go back and add touches. Ink the weeks work. Scrape off old ink with a razor or X-acto knife. If it's anew pen nib wash it in soap and warm water. If you keep it higher, you'll spill it.
Ink loves to jump onto artwork.
Don't try to ink a whole cartoon at one sitting. You'll get tried, bored, sloppy, your hand will smear a line you thought was dry. Go back and erase the pencil line after all the ink's dry. Go back over the work again and look at it. Indicate with pencil any place you feel you need to fill in with black.