I hated that sensation it was bloody awful. If panadeine forte works for you then take it I went a bit further and took an endone just one at night which was awesome and lasted longer so I didn't need to take as many pain killers. I didn't have a seroma in my left side which had the lymph nodes removed I had one in the right side which didn't funnily enough and I still think it was because the drain was taken out too soon. I ended up in hospital overnight with IVAntibiotics as no one wanted to listen to me when I said it was sore red and full of fluid , I was told it will dissipate on its own!! Which was bullshit as I had to have over 200mls drained from it. And I'm a nurse so I had some idea! But after that it settled down and the discomfort decreased quite quickly after that. You could try a heat or cold pack but be careful with the temp of the heat pack due to the numbness If you get any more fluid build up or just don't feel right take yourself back to the hospital. I also found a warm bath helped too. Trust your gut on how you feel lovey. Margie ❤️