Brief Answer:
Irritation of the femoral nerve which supplies the inner part of the thigh

Detailed Answer:
Hi.
Thanks for your query.
To recapitulate: Female/79 - consulted a Doctor - lump in upper thigh - ultrasound - swollen gland - on antibiotics since Wednesday - now there is soreness going down the thigh to about 5 inches above the knee - inner thigh - going back to Doctor on Monday - wants to know whether to be super concerned now?

Since the lymph node/s are involved in an inflammatory process, it is possible that the femoral nerve which also supplies the sensory part of inner thigh must have got irritated/involved into the process of inflammation hence causing the soreness going down the inner part of thigh as you have explained.

If there are no symptoms or signs of extended swelling, fever, chills, you may continue on the antibiotics or may change over to another antibiotic and add on anti-inflammatory medication with painkiller properties, probiotics.

Referred pain or actual nerve pain indicates that the nerve is involved and should be of concerns.
You may visit the ER and get additional medications as advised. You also get a clinical evaluation and examination by a Doctor, try for by a General Femoral nerve might have got the information

You may need an ultrasonography
Take bed rest.
Take care.
Ultrasound of the whole abdomen and the groin and upper thigh area.
FNAC of the node under ultrasound guidance.

I hope this answer helps you, please feel free to ask for further relevant queries if you feel that there is a gap of communication.

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Brief Answer:
Watch for symptoms and signs

Detailed Answer:
As advised earlier, watch for other symptoms and signs like:
Swelling of the thigh
Painful movements of the thigh, difficulty in walking.
Fever with chills
Or anything unusual for you.
- If such are present you need urgent investigations.
- If no difficulty as above, you may wait until Monday.

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