Baby colds can hang around for ages. A little red rash is also common and a harmless sign of a viral infection (aka the cold). The health direct line told me once that the rash should clear up by the end of the third day / fourth day, if not get her checked out again, especially if, as MadB says, she seems lethargic, isn't drinking or keeping fluids down, listless, feverish etc. but as I said baby colds can hang around!