It is mandatory for the doctor to discuss the pros and cons of the operation and the major likely complications. You will appreciate that the doctor cannot possibly discuss each and every complication for this would take a long time and would engender unwarranted fear in the mind of the patient. Doctors have therefore perforce to restrict themselves to the more likely and more serious complications.
I am not aware of the exact location of the lipoma and its relationship to nerves that convey sensations from the fingers and hands. If the nerves were passing through the lipoma, they are vulnerable to injury when the lipoma is removed. Doctors can and do take precautions to minimise the risk from such injury.
You must discuss with your doctor the information provided to you and whether or not nerve injuries were referred to.
I cannot determine from this distance whether or not your doctor's diagnosis is correct. The tissue removed must have been sent for histological examination. The report will tell you whether or not the swelling was truly a lipoma.
As regards the nerve injuries, you could see a good neurologist and also get this consultant to advise you on the information to be gained by a test such as electromyography combined with nerve conduction studies. You could also see a neurosurgeon or plastic surgeon who does peripheral nerve repairs. This specialist will be able to advise you whether injured nerves can be repaired.
If your loss of sensations follows surgery and is a consequence of injury to nerves during removal of the tumour, this is unlikely to spread to involve other parts of the body.