Rough night

So we had a bad night last night. Liam has always been freaked out by ticks. (Ironic, no?)
Over the course of the weekend, we've found two ticks- neither of them actually attached- on him. The first his dad found crawling on him. The second was on the table right next to him last night, he must have brushed it off without realizing it. His OCD has gotten worse lately. He REFUSES to take a shower until it's dark. He says it just feels "wrong". So we're dealing with timing other things around this latest issue and trying to talk him into giving it a shot since soon it will be light until after his bedtime. In addition to that, he had a complete meltdown absolutely convinced that there were ticks on him. I told him I would do a thorough check. He wouldn't let me near him, he was sobbing and hysterical. He finally went upstairs to do his homework only to come down a few minutes later still hysterical, telling me that after every problem he did he needed to check his whole body for ticks, he says he knows that they're there and he just can't find them.
I finally sent his dad upstairs to talk to him because I was feeling so helpless trying to assure him that nothing was there and telling him to let me check for him. It took his dad a half an hour to calm him down. Liam said he was never going to go outside again. I told him that because we have a cat and dog who both go outside we can't prevent the ticks getting in the house.
I'm hoping for a speedy stop to this since the kids can finally enjoy the outdoors.