The first step of this puzzle is obviously to fill out the cryptic crossword. The finished grid should look as follows (see the Addendum for how each word is derived):
The key step to this puzzle is noticing that every word in the grid can become a new word by adding a letter to its front or end (here any case like adding an S to the end of a word only to make it plural is not considered "changing the word" as its meaning is not significantly altered). For instance ELATED can become RELATED, or THOUGH can become THOUGHT. However in many cases the added letters and even their positions (start/end) are not unique, and there is no clear way to use these letters anyway.
Here the border supplies a hint - the smaller dots are strategically placed at the start/end of those words that touch the edge of the crossword frame, suggesting that the letters that can be appended in these positions are the important ones. The puzzle's title also confirms this - even the filled out crossword is in fact incomplete, and in order to "complete" it we must extend the grid beyond its frame as dictated by its edge words.
Still, however, some of the edge words have more than one allowable letter that may be added at the appropriate end to create a new common word. Specifically, we have:
It is clear here that each cluster of three creates a new word however, and this new restriction singles out a unique letter to be appended for each word. The resultant words, reading clockwise from the top, are AID, DAM, ARE, MID, ANT, PEE, RAG, and USE.
Considering again the border, we apparently must fill in the larger white circles in order to complete the crossword. It's likely we'll have to use the letter-appending trick again, and indeed here each large circle lies at the end/start of two of the three-letters words signified by the small circles. In fact in all but two cases, only one letter may be placed in the position of a large circle in order to make two new common words from the words adjoining it (e.g. on the left side of the grid, while USE may be followed by D/R/S and RAG may be preceded by B/C/D, only the letter D satisfies both conditions). We thus end up with:
Reading clockwise from the top-left, there is clearly only one possible word formed by the red letters (those at the large circles' positions) - REPAIRED, which describes what we've done to this previously incomplete crossword.
The crossword words are derived as follows, given in the same order as the clues:
|The answer is: repaired|