I suggest that you measure the span of your fingers and keep checking it to see if the contracture increases. I'd also suggest that you take pictures (I wish I had), or as someone suggested, use a copy machine to take pictures to compare to see if it is getting worse. It could be very slow and you not notice.
If it progresses, you might consider radiation therapy (RT). That works best early and when it is active.
Read about RT and other treatment options using the links in the menu on the left side of this Forum. There is really good information there. You can also use the "Search web site" to connect to postings on this Forum about questions that you have.
Come back on the Forum and ask any question. People will describe their Duputren's Disease. Everybody's is different, so expect that yours will likely be a little different or a whole lot different. Finding out how others were/are affected can help you recognize what is going on and what your options are.