[SallyintNorth]

The one where the position of the lumps is important is CLA - Caseous Lymphadenitis ; you can read about it on the NADIS site here
That's why I asked Amanda whether it was big lumps at the angle of the jaw 

Abcesses at the site of vaccination are common, even if full aseptic precautions are used.

[Marches Farmer]

Lumps at vaccination site are generally worse on younger sheep (thinner skin) and if the vaccine is in a thick, oily adjuvant (carrier medium).  Nearly all my shearlings had one when I vaccinated with Footvax but fortunately it worked so well I only had to do it once and haven't seen it since 2007.