A couple of options.Try practicing those trills very slowly while playing the right hand part as well. Play them strictly in time as 32nd note trills with the termination, two 32nds to each of the 16th in the right hand. Sometimes the rhythm of the right hand can help the left hand trill.Make sure to drop your arm weight gently onto the beginning of the trill; try to find some movement of the upper arm or elbow that frees up the tension in your left hand - the more you worry about the trills, the tenser you get, so you need a trick to release the tension. My teacher always gets me to move my arm whenever my wrist or fingers get tense.If all else fails and you have no other option, just play a mordent with a termination, or take out one of the repetitions in the 32nd note trill. Better a slower trill or one with fewer repetitions played cleanly and calmly than one that causes you to tense up and panic.