Scar infection

Hello fellow BC peeps

i had a lumpectomy and lymph node removal nearly four weeks ago.  At my follow up was given good news that I don’t need chemo, just radiotherapy and oestrogen blockers probably.  However this weekend my affected boob became very hot, red and swollen.  Ended up via 111 service at local out of hours surgery where doc on call said it was an infection and has given me a weeks course of antibiotics.  

What I thought was scar tissue near my “lump” scar is fluid, apparently as a result of the infection around “lymph” scar.

Has anyone else had a similar problem?