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...
Oh @Blossom1961 your onc needs to learn to google!
https://www.drugs.com/sfx/herceptin-side-effects.html Didn’t take me long and I note I have the tiredness after treatment so tired today(treatment was yesterday) I’m itchy today, pain in hip and knee (herceptin or armidex who knows) I occasionally have the metallic taste, stuffy nose is me really no surprises
if your gp is sympathetic use her instead of the onc