Thank you for choosing DoctorSpring.
There is NO reason to worry and yes your being bit paranoid.
First of all - It is highly unlikey that there will be any blood on the Phlebotomists hand. Phelobotomists are professions deals with blood everyday and they know better than any to manage and keep blood without any spillage.
Second - There was only indirect contact. (No direct blood - to your body). Indirect contact has near zero risk
Third - Only contact with intact skin. Most blood related transmission (as in HIV) cannot occur via intact skin. That means there should have be an open wound or abrasion in your thighs for the transmission to occur.
So putting all these together your concern we can see there no reason to be worried.
Hope this helps
Feel free to ask follouwp questions