can someone explain that

can anyone explain to me what a calayxs is? (sorry if spelt wrong) all i know is that they swell on the last bits of flowering? does this increase the size of bud and how can you tell when they are swellin?

You can see them. They are the seed pods (hopefully with no seeds inside) Not sure that they so much swell but the other stuff recedes making them more visible

They swell, well hopefully, with resin to fill the void in place of a seed. A combination of that and the stigmas dying create the illusion of them receding into the calyxes...