General Notes

Unfortunately, there is neither a townland called Drumborisk nor a parish called Currin in the online Tithe Applotment Books at either the National Archives of Ireland website nor at the FamilySearch website (which seem to be copies of each other).  However, two adjacent townlands ARE there.
Parish of Aghabog:
There is an Edward Mackey in Doohat, holding 2/3/11 arps.
Surname    Forename    Townland/Street    Parish    County    Year
Mackey    Edward    Doohatt    Aghabog    Monaghan    1833
There is a Pat Mackay (yes, with an "a") in Glen.
However, the County Monaghan website DOES show the following Mackeys in Monaghan:
Mackey    Christy    11    Donnyluck
Mackey    Edward    17    Drumborish
Mackey    Edward    21    Drumborish
Mackey    John    19    Drumborish
Mackey    Will    9    Donnyluck
Mackey    Will    18    Drumborish
This is not unusual.  There was often more than one TAB and therefore depending on which version was being copied, a complete parish could be missing, or just several townlands.  On the other hand, how did Doohat and Glen end up in another parish, Aghabog, but not adjacent Drumborisk?!

RootsIreland has these:
Source    Surname    First Name    Year    Townland    Parish    County    
    Early 19th Century Tithe Books    MacKey    Edward    1827    Drumborish    Currin    Co. Monaghan    
    Early 19th Century Tithe Books    MacKey    Edward    1827    Drumborish    Currin    Co. Monaghan    
    Early 19th Century Tithe Books    MacKey    John    1827    Drumborish    Currin    Co. Monaghan    
    Early 19th Century Tithe Books    MacKey    William    1827    Drumborish    Currin    Co. Monaghan