Not very sure, as it depends on the preparation and other factors of the dried films before doing SEM, but these look like the activated form of platelets. When the platelets become active, they change from hair-like to discoid-like structures. You can see my published paper for reference.

https://www.nature.com/articles/s41598-020-76082-6

Did you activate the platelets by weak or strong agonists? Does the platelets isolated from healthy blood donors or used apheresis platelets?

The visualization of platelets is slightly different because there are a several platelet populations such as resting platelets, stimulated platelets, procoagulant platelets, spreading platelets or ballooned platelets or others. Each population can indicate particular issue so the protocol you used for this image is important. Good luck.

We collected blood from cancer patients, isolated the platelet rich plasma and made a smear on cover slip with it. Then we followed the protocol for sem microscopy sample preparation Fahad Alshehri

If it is not artifact from the slide then I think it is a resting platelet, but you can scan all the slide and decide if you see more cells like that or just smudge cells and few cells. Another thing you can activate the PRP by 1 U/ml thrombin and see if the shape is change to the activated platelets then it is clear for you the previous shape is resting platelets.