If you request a computer analysis of the finished game, you get a graph of the evaluation, and "blunders", "mistakes", and "inaccuracies" marked in the move list, you can also click on the "learn from your mistakes" button (after the analysis is complete) to go over them and try to find a better move.
See the bottom of this page for example:
^Click on link to game right here.^
Switch the tab to "computer analysis" (other tabs shows move times graph, crosstable, and FEN and PGN) and you will see all the relevant data, at bottom left is the bad-moves tally and the "learn from your mistakes" button.
Analysis is provided by the Stockfish 9 chess engine.
Bear in mind that computer analysis uses lichess's limited supply of server computing power, and that there is not enough avalible to analyze every single game everyone plays.