My dog has been suffering from a tick invasion for the past couple months. My cousin, also a dog owner, sent me a collar for him to wear, telling me it's supposed to work wonders in terms of repelling ticks. So, I bathed him and put the collar on. So far, I've noticed that whatever ticks he had left on his body seem to be "jumping ship", so to speak, in that I've found a few just clinging to his hair, rather than biting him. However, he's been kinda lethargic all day. He's still playful, and still reacts to the usual stimuli (for example, he'll try to bite any strangers that touch me, even if it's just a handshake), but he seems very tired. Could the collar be somehow responsible for this? Should I take it off?