Swollen Scent gland? (Syrian)

[Lizwig]

So I've noticed the past week or so that the left hip scent gland on my Donny has been a lot larger than normal, as it's more prominent and raised than the one on his right hip. There's no redness or flakiness around the gland and he isn't bothered in the slightest when I touch it.

I am wondering if the gland is perhaps blocked?

I only ask in concern as Donny is an older hamster (coming up two years now.) He's lost weight and his fur has thinned, and he drinks a lot of water, otherwise he's a very active hamster and shows no signs of arthritis.