Lump on testicle

Anyone have any idea, what this could be, not sure if lump or just irratated. Thanks 

Hello - this looks abnormal to me.  Is it new?  Inflammation of dark skin doesn't usually turn it white (although scar tissue may), so your vet might propose a biopsy or (because scrotal skin doesn't tend to heal very well) scrotal ablation (which will require castration if not done already).  Obviously your vet can examine the scrotum in person and may be able to see something that I haven't, so their opinion is more to the point that my speculation, but we would recommend seeing them soon.