Finger swelling is a major sign of pitch issues. ...
Minor correction: Finger swelling MAY BE a sign of pitch issues.
If your fingers fit fine when you finished bowling last time, and now, be it 1 day or 1 week later, your fingers are too tight, before you ever throw a ball, it more than likely has nothing to do with pitch.
It could just be human nature: our extremities shrink and swell all day and all night long; they vary with temperature, humidity, activity, food, liquid and salt intake, as well as medication use.
Some people's shrink and swell more than others.