If your count was 23/300, that is more than double the treatment threshold. I am sorry to say, but you may have treated too late. On the hopeful side, formic treatment is 14 days so it is still working. You really should not disturb the hive during those 14 days. If it survives, I would consider treating again after 30 days. You are on the wrong side of the numbers game. Mites are peaking and bee population is declining so your result so far is not really surprising. J
