Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Get urgent or emergency help if a finger becomes pale, blue, cold, or suddenly loses sensation, especially after treatment or an injury.
Seek prompt medical advice after a procedure if you develop increasing redness, warmth, swelling, discharge, fever, worsening pain, or a wound that is opening.
New persistent numbness or difficulty moving the finger should also be assessed.
Uncontrolled bleeding or rapidly increasing swelling after a procedure also needs urgent care.
Arrange a routine appointment if you notice a new palm lump, a firm cord, or a finger that is gradually becoming harder to straighten.
Assessment is also appropriate if the change affects washing, dressing, work, hobbies, or your ability to place the hand flat.
The article also says
Sudden severe hand pain or a sudden inability to move a finger is not typical of Dupuytren contracture.
It may indicate an injury or another hand condition.
Every sign above is quoted from the sofidex article on Dupuytren contracture. If you are not sure, err upward — it is always reasonable to be checked.