Flea collars can be poisonous. I’ve had patients have hair loss, to seizures and death from flea collars and shampoos. And, right now, many people are finding nothing works more than 2 weeks. I’d get some topical thing from the veterinarian – frontline or advantage. In two weeks, you may see more fleas. In the heat of the summer and moving into fall, fleas hatch every 2-3 weeks. So, when the flea product starts to fade, there is a new crop hatching. Long-term, know until we get a good hard freeze the nasty critters will still be around.