Can You Take Unisom Sleep aid With Tylenol pain reliever?

i had surgery on my knee for a cracked growth plate a few years back and the doctors put two pins in my knee, &Lately I havent been getting to bed till atleast 3:30am or 4 But when it gets Cold my Knee tends to get sore &aches with no sign of it letting up .. So i Took 4 tylenols & was hesitating on taking a Single Unisom sleep aid pill, is this dangerous? im not taking any chances Lol.