My lymphoedema therapist would recommend massage but you need someone qualified to do it, a lymphoedema specialist, not just any masseuse. Also good to check with your surgeon before starting. Basically you want to very gently encourage dissipation without encouraging infection. A lot depends on location and duration too. It isn’t necessarily fast so if the seroma is relatively recent you might still want to give it some time to dissipate naturally. I had a very large seroma for a long time - apart from the risk of infection by draining, seromas are dab hands at refilling! Slow and steady is the ticket to get it to go and stay gone. Irritating though, mine would audibly slosh when I bent over!
Mine is like an mango, it’s under my on my bust like a lemon and it’s now under my arm as well , when just standing it protrudes in front, and under my arm , is very painful. Let’s hope ours goes away by itself xx
