Onco says Herceptin does not cause side effects even though the manufacturers of herceptin says it can. So, the peripheral neuropathy, sore throat, itchy rash, ridged and cracked nails, breathlessness...
Just a thought, is that your knee? It looks rather like infected hair follicles. I had similar post chemo when my hair was growing back, particularly anywhere my clothes rubbed. Knees, hips, shoulders. I never knew I had so much hair on my back, until they all behaved like they were ingrown when they reappeared. Mxx