This year's Blessing of the cough drops falls on Sunday Feb. 3. For St Blaise, LU points to Sacerdotes Dei p963, which is actually on page 960 of my copy. So, searching the U. Florida Motet database, one gets:

In. Sacerdotes Dei (2 anon. hits)
Gr. Gloria et honore (Forster, Walter, Mergot, G. Asola, Guerrero)
Alleluia, Hic est sacerdos (Corteccia, Asola)
Co. Posuisti Domine (F. Duc)

You could also just use the permissive version of "O Jesus King most Wonderful", with the updated line "Thee You may our tongues for ever bless".