Tear up agitatedly again after opening (8)
I believe the answer is:
aperture
'opening' is the definition.
(aperture is a kind of opening)
'tear up agitatedly again' is the wordplay.
'agitatedly' indicates an anagram (I've seen this in other clues).
'again' becomes 're'.
'tear'+'up'='tearup'
'tearup' is an anagram of 'apertu'.
'apertu'+'re'='APERTURE'
'after' is the link.
(Other definitions for aperture that I've seen before include "Opening, mostly small" , "Eye" , "Hole, gap" , "Opening (on camera, for example)" , "Opening, gap" .)