A jawed leech such as Macrobdella decora attaches with a posterior sucker and cuts with three radially arranged jaws bearing fine teeth. The bite is a shallow Y-shaped incision. The animal holds on with suction and with the friction of the wound edges, not with hooks embedded in flesh.
Breaking the seal is straightforward. Sliding a fingernail sideways under the narrow anterior sucker interrupts the suction, then the posterior sucker is displaced the same way. The wound bleeds for some time afterwards because leech saliva contains anticoagulant and vasodilator compounds, which is normal and not a sign of retained mouthparts.
Heat, salt, alcohol and insect repellent all provoke the leech to detach abruptly and can cause it to expel gut contents, which is the actual infection risk. Standard first-aid guidance for leeches is therefore mechanical removal followed by cleaning. Rates of clinically significant infection after ordinary leech bites are low and not well quantified.