Hi thanks for your question.
The lump you are having on back of your neck and has increased in size most probably could be a lymph
node.Your G P is right is saying that.Lymph nodes enlarge in response to infection in their vicinity,here again G P IS right ,but the question is what exactly this itchy infection is .Staph infection should respond to 2 antibiotics.The other possibility could be fungal infection
.Three long dark redish streak below the lump could be due to suppuration (puss formation) of lymph node.I would suggest you to consult a dermatologist
who may examine you to determine what this itchy rash
is.He/she may take materail ooszing from the sore for culture sensitivity and may prescribe drug depending upon culture sensitivity.Keep cleaning the sore with alchol swab.
Hope this answers your question.