Dr. Neill says the best thing to do is cover up exposed skin, but also recommends using an insect repellent containing DEET. If a person does get bitten, Dr. Neill says that using a cool compress or calamine lotion may help. He also recommends using an antihistamine. He says that patients should see a doctor if “you have any local redness or swelling, especially if it persists for more than a few hours or a day, for a spider bite, if you have any necrosis, or darkening at the center of the bite.” For tick bites, Dr. Neil says, “If you do find a tick, aside from getting it off, it’s probably going to be helpful for you to chat with your primary care doctor to see if you need any specific treatment.”