S. R. Faruqi:

This verse is interesting because it makes clear that in the latter period of his life too, Mir versified themes that had envisioned becoming a 'sugar-fly' [=a fickle lover]. The 'greenery of the down' on the beloved's face has greatly increased; thus his beauty has diminished. In such a case, how would there be attachment/affection?

Here the word bahār is extremely fine. The beloved's face is a 'rose'. But the 'greenery of the down' has so surrounded it that its beauty (that is, the 'rose') has become hidden. An excess of greenery too occurs only/emphatically in springtime, but what use is so much greenery, when the source/origin of the springtime would be hidden?

So to speak, the abundance of the springtime has laid waste to the springtime. There's also the point that greenery is called 'strange, alien' [sabzah-e begānah , referring to weeds]. Thus when many 'strangers/aliens' have collected, then the beloved is held in less esteem.

For the 'greenery of the down to emerge beyond the ears' can also mean that no difference has remained between the beard and the hair of the head-- as if there was a single flower, and thousands of thorns or grass-blades had surrounded it.

FWP:

SETS
MOTIFS == [BELOVED IS A BOY]; SPRINGTIME
NAMES
TERMS

I have nothing special to add.