Recovery after axillary clearance

I had axillary clearance 12 days ago with the removal of 13 lymph nodes. I’m a bit bowled over by the severity of the aftermath of the surgery, including nerve damage and cording. I’m most concerned about the size of my axillary wound swelling, which is quite large (maybe 8cm x 10cm), painful and hard. It feels like I’ve got a tennis ball under my arm. Is this kind of swelling normal and I wonder how long it might be before I see improvement? Thanks for any thoughts.