We knife cut about 30 calves a year. They are a little smaller than the ones you describe, however, there has always been some that have impressive swelling. It will go away. A week out, I think that is normal for you to have what still appears like a pair of testicles down there, size wise at least. The offending tissue won't behave like a pair of them movement wise. When we cut a larger one we usually use emasculators but this far out bleeding should not be an issue for those calves. We don't give any penicillin so you have already done more than I do. I check them every day and make sure they are all nursing and up moving around. Depending on where you are, fly strike could be a problem this time of year (we cut sometime in May when bugs are not bad) but honestly I think you are just seeing normal swelling. If this was your first time doing it, maybe you might have caused a bit more swelling than normal with hesistant cutting of the the scrotum or cord? This is just an idea and I am sure you didn't do anything wrong but just thinking that if you were hesistant in slicing through the bottom of the scrotum it could cause more tissue irritation. Long and short of it is, if they seem ok, I bet they are and I don't think the swelling is uncommon and you probably just are nervous about your first time doing it solo. I don't do the actual cutting and I would be a worry wart if I were!