@bevvzy , I would be taking your GP's advice and going to the lymphedema clinic. You don't want to muck around with this and the earlier you catch it, the better the outcome. At the clinic they will have skilled staff who can help you immediately. I have mild lymphedema that was caught reasonably early. I tried to deny it and hated the fact that I had it... it's a case of cancer the gift that keeps giving. However I am now more accepting of it and do lots of self massage and wear a garment most of the time. 3cm is actually quite a big difference and with the pudgy feeling something that needs to be addressed quickly. Lymphedema is not discussed enough by our surgeons and something that is often forgotten. It won't go away on its own., however you can have quite a good outcome if you get onto it straight away.
Hugs
Paula xxxx