Could lymphedema be a possibility after the removal of one lymph node?

I don't think it's common but also i don't think it's impossible.

My mother has lymphodema from her breast cancer operation and she does "water therapy" . She runs the shower over the affected area and it soothes the pain for a while.

Lymphedema can technically happen with any lymph node removal, however, significant numbers of node removal tends to be associated with higher risk of lymphedema. Sentinal node biopsies (removal of one node during breast cancer biopsies) have resulted in lessed, but not complete reduction of cases of lymphedema.

I would say that this would be an unusual presentation for lymphedema, but the fact that it is persistent since the flight is highly suggestive of it.

Ultimately, you will probably require some form of compression garment if you want to have it controlled. Some forms of massage are permissible, but deep tissue massage may be doing you more harm than good.

I know it would be a stretch to find a physician who is actually knowlegeable on lymphedema, but I would start by searching for a vascular surgeon or a physiatrist who specializes in lymphatic disorders for a more definitive answer. If thought to be lymphedema, you will require a specialized compression garment.