I am sure if he thought there was anything sinister he would have been more concerned. You appear to have an infection that is responding to treatment. If it is still red and inflamed after you finish your antibiotics I am sure you could be referred back again. Or your Gp can monitor it he will receive a report of what the findings have been so should be able to reassure you.
I'm sorry you are still feeling so anxious. Do give the helpline a call to talk over how you are feeling. I know I mentioned it on another thread but here are the details again- they are open from 10-2 today and 9-5 on weekdays. 0808 800 6000
Very best wishes