It's wise not to underestimate even the smaller pterosaurs. Even the diminutive dorygnathus - given enough time and effort - can fit a whole human into their little stomach if they're hungry enough.
This poor dear's regretting their choice in dinner somewhat, experiencing one doozy of a stomachache from their belly being stretched so much. It's too late to take it back now, and no amount of regret will change their situation or their prey's!