Hi BCinParis
Congrats on finishing chemo and surgery - you have completed the worst bit now! Hope you are doing ok.
Your pathology results from surgery will likely guide how your Herceptin is given. If you have a complete response (ie no cancer), you can have the subcutaneous injection of Herceptin. If there are cancer cells left you may be recommended to have Kadcyla intravenously (which is a chemo/Herceptin mix, but much more gentle chemo than what you have had).
I had pCR at surgery, so had the injection in my thigh. I still had to attend the chemo ward at hospital to have it, but it took much less time. Virtually no side effects - some local pain where they inject and a bit of tiredness. To reduce pain, ask the nurse to inject slowly and remember which thigh they inject and alternate legs.
All the best and hit me up for more questions if you have any xx