My hamster has a brown-ish/purple lump... HELP!!

[abby.1991]

I have a 3 month old syrian hamster he has a 7mm brownish/purplr lump on his back, looks a bit like a very small birth mark but it is raised from the skin.
Please help?
Abby

[souffle]

Is it his scent gland at all Abby? They have one each side on the sort of top of the hips / back area. These are normal and can darken with age. I have some pics onthe thread 'syrian scent glands'
If his wheel is too small the spindle can also rub the back and cause it to get scarred / abrased and this can look like a lump so check he has a nice roomy wheel and can run staight.
If you have a picture that would help.