FWP:
For more on the possibilities of a 'lamp-tree'-- literally, a 'cypress of lamps'-- see the discussion in M{1650,2}. Shadan seems to think of it as an actual kind of fireworks, but his notion may post-date Ghalib, or may even be a back-formation from the verse itself.
If the speaker ever has the leisure (which he perhaps never will), he will show the world a tamaashaa , a 'spectacle'-- perhaps even one with both worldly and mystical dimensions.
Alas-- he is so beset by griefs and cares that he scarcely has even the breathing space it would take to light a fireworks-tree and watch it burn. And yet the burning wounds/scars in his heart could generate many such fireworks-trees. Every one of these wounds is ik tu;xm -- a single seed? Only a seed? A certain seed (particularly identified)? A unique seed? An excellent or preeminent seed? In view of the possibilities of ek (see the definition above), it's left up to us to decide.
Whatever kind of 'seed' the wound may be, it's as brilliantly efficacious as the radiance of fireworks. Or rather, it would be-- if the speaker's leisure (or lifetime?) would be long enough to activate it. In fact such wounds/scars can even dazzle like the sun itself, as in {62,8}. And the chiraa;Gaa;N can be treated like a carnival display, as can be seen, with other examples, in {5,5}.
Note for grammar fans: On the very clear use in the first line of the perfect verb form as a subjunctive, see {35,9}.
Nazm:
That is, from every single wound/scar a fire-filled lament will issue, for which a 'lamp-tree' has been used as a simile. (11)== Nazm page 11