Hamstring injury

Hi all,

I have hurt my hamstrings on my left leg, and I feel like this is a remnant injury from about 4-5 months ago. When I first hurt it, I went for physio and it healed, but I'm guessing not completely.
However I do not feel like returning to physio this time. I plan on taking care of it at home first to see if I can cure it myself.

I was just wondering if it's ok to keep doing the usual stretches I do to stay flexible, or if that'll just make the injury worse. I just don't want to lose my level of flexibility.

Thank you!