First of all to confirm the diagnosis more information from history is needed and patient has to be examined.
Is there severe pain in the swelling, is there redness, is there any history of trauma, are there any other similar swellings in the body,previous history of this swelling ??
This does not seem like a lymph node.
It could be a cystic swelling may be a ganglion cyst , implantation cyst or sebaceous cyst.
The swelling has to be examined first by me to determine nature of swelling and further line of investigation.After examining patient may require fnac or usg.She may require surgery if it’s a cyst or local therapy ( if ganglion).
Next Steps
Examination of the swelling then further line of investigation and management