The bald spot doesn't look very swollen, but the eyelid does. I'm thinking that the dettol may have gotten in the eye, which could cause it to get very inflamed like this.
I reccomend rinsing the area with clean water for two minutes. Do not apply dettol to the cat anymore - as a general rule you should not apply dettol to animals, because it can cause damage to the skin.
The best thing you can do is take Misty to the vet. The bald area could be ringworm and the eye could be damaged and require further treatment. A vet would be able to diagnose the problem and provide the best treatment options.