Also do not understand those who say that Milan played badly, rather Lecce played well, motivated with a huge dedication and in principle could have scored 3 goals in the first half and probably then Lecce would have won, but Milan pulled together and could win in the second half, scoring 3 goals, but somehow miraculously in the end Lecce bounced back.
People said so because they did expected AC Milan to beat Lecce so even Milan scored three goals and pulled the match to a draw, it is not what they thought before the match. In their opinion, AC Milan gave Lecce chances to score 3 goals in the first half because they played worse than expected. What AC Milan did in the second half is to fix their mistakes so in general it is a bad match for AC Milan.
So it's more likely that Milan just didn`t expect such a dedication from Lecce and after Milan lost the thread of the game, but at half time apparently the coach found the right words and the team played as it should, first confidently winning back, and then playing to win, a little bit unlucky, so Milan would have taken away 3 points.
This draw with AC Milan can give Lecce more confidence in next matches that is so important for them to end the season with a position out of relegation area. Lecce stands at the 12th position but with 20 points, they have only four points more than Sassuolo at 18th position. If Sampdoria can improve, Lecce might fall to dangerous position and they can not play carelessly with thinking that Sampdoria won't be able to improve.
So there is no loss of control of the team, Milan can improve, there is a small misfire on the way, but 1 point is still not zero.
AC Milan will have more pressure from Juventus, Inter Milan and even three clubs behind including Lazio, Atalanta and AS Roma. Their second position now is no longer safely which can be taken over by other clubs.