Make playing gentler
Try short sessions with breaks and fret just behind the metal fret rather than halfway between frets. Find the least pressure that still gives a clear note. If a guitar is unusually hard to play, a professional setup may help.
Know when to stop
Stop for sharp pain, numbness, swelling, blisters or symptoms that remain after playing. Let your hand recover. If symptoms keep coming back, seek advice from a healthcare professional rather than pushing through.
Is pain necessary to learn?
Mild fingertip sensitivity can happen at first, but do not ignore sharp or lasting pain.