Scary experience working retail

I work retail. I get a lot of men (mostly men in their 40's or 50's, it really creeps me out, I just turned 18) flirt with me. I usually just ignore it and answer their questions about the product (shoe store) and I send them on their way. Well, about a week ago this man brought in his little girl, and he needed shoes for her. I helped him fit her (he didn't know her size) and the girl was very playful and sweet. She was about 14 months. He kept on referring to me as pretty lady. I didn't think much about it, it happens a lot and it doesn't bother me that much. Well I sent him on his way with a couple of pairs of shoes for his baby. He came back in last night and seeing me he said "I came back to see you" I ignored it and asked if I could help him find anything, he pointed to his shoes and said he wanted another pair similar to those. I showed him the ones we had and he picked one out and he followed me to the checkout counter. I did the procedure (sizing and mating the shoes, asking about the rewards program, offering socks and shoelaces). I kept it short and sweet, since I didn't like the vibe he gave me. As we were waking for the chip reader finish, he looked at me and said "do you have any idea how adorable you are?" I said thanks, and at this point I cut it completely short, gave him is receipt and walked away as I didn't like the way he was looking at me up and down. I got my manager and told her, she stayed with me until he left. When he walked out the door she went back to packing shoes to ship in the stock room, so it was just me by myself on the floor again. About an hour later he comes back. He walks up to the counter and says "I just needed to see you once more...." and keep in mind this guy is like 40, so I'm a little on edge about it and he said he changed his mind about the shoes. I got my manager over the headset and said he needed to exchange them, and he got mad. "You're getting someone else to help me?! Do you not like me?!" I simply stayed that sales associates are not permitted to handle returns or exchanges. I walk away he follows me. I run into my manager and she takes it from there. She ushers him to the counter and instructs me to wait in the stock room with the door closed. I did so and she came back 30 minutes later. She said he kept on asking for me and got angry when she said I was leaving for the night. This freaked me out guys, it makes me feel unsafe, especially since i have to walk in a parking garage to get to my car at night, usually 11-12 PM. I carry pepper spray but I feel like I need something else to ease my mind. What do you suggest?