Here’s what MediRabbit says:
The use of over the counter products against mite or ear mites should be avoided. Most contain pyrethrin. While one of the least toxic insecticides for animals and rabbits, pyrethrins/pyrethroids are neurotoxins which lead to continuous “firing” of nerves. Observed problems in rabbits include limb paralysis, seizure, coma, tremor, sometimes death.
Many of those products contain additives that prolong the effect of the pyrethrins, and inhibit the breakdown of these products in the body. They can lead to toxic reactions in rabbits. Piperonyl butoxide is one of them. If no immediate death, there should be **slow** recovery with time, around 48 h.
Did you wash the spray off as soon as you noticed a problem? This would be one of those rare occasions where a bath really would be warranted.
Have you notice neurological symptoms yet? You really do need to take your bunny to a vet. They will be able to treat the symptoms and provide support such as oxygen and fluids if needed.