The cause of these blisters
Blisters under these joints are due to the structural (anatomical) issues with the feet, the big toe joint and the little toe joint are contacting the ground before the other three middle joints, increasing the amount of pressure on those joints. Usually, feet with high inside arches are prone to blisters on these joints.
How to help prevent these blisters
Engo patches are applied to the insole inside your shoe, apply on to insole that correlates to blister affected joints.
If you are unsure where the joint is in relation to the insole, then put a fabric plaster on the blister prone joint, mark it with a permanent marker pen and place the foot back in the shoe, the black marker pen should rub off on to the insole. Accurately marking the area of pressure on the insole, apply a oval engo patch on the marked area on the insole.
Poron insoles cushion and allows the big toe joint to work harder, reducing the pressure from the ground, which in turn, prevents blister s forming on the big toe and little toe joints
Armaskin socks again will also decrease the shear on that area of the big toe joints but they may not be able to do it totally by themselves and would need additional recommendations as pressure under the big toe joints is considerable
Darntough have cushioning in their socks that will help with increasing the shock absorption under these joints and with their moisture wicking ability reduce the sweat left next to the skin
Hoka one one running shoes and boots are designed with a large shock absorbing rocker sole. From a foot functioning aspect, the big toe joint can drop into the shock absorbing sole without receiving the jamming
Biomechanical Assessment is needed to be done by a Podiatrist if all the measures above have failed to resolve the blisters on the big toe and little toe joints under the foot They will be able to establish why these joints are experiencing an increase of pressure to cause the blister in the first place, a podiatrist may be able to make a simple insole or a prescription orthotic to solve the Biomechanical cause of the blisters. You maybe also experiencing ankle, knee, lower back and sometimes neck pain which could very well be caused by the big joint dysfunction.