Should I get a second opinion about my swollen, hurting thumb?

[AH93]

I am a total klutz and ran my thumb into a wall, really hard, and felt a pop. My thumb then went numb, started to swell, and then began to tingle. About an hour later, it felt like someone had taken a sledge hammer to my thumb joint... I took some ibuprofen and put ice on it off and on, just like I would with any other injury that swelled up. After 18 hours, the swelling had not gone down and the pain had gotten dramatically worse, so I went in to an urgent care facility and had my thumb checked out. The doctor wasn't asking many questions and barely touched my thumb to inspect it. He ordered x-rays, but he said they were normal. Then out of nowhere he said he thought it was an infection and sent me on my way with a prescription for antibiotics, no suggestions for home care, no explanation as to how it could have become infected. He didn't even do a blood test... Keep in mind, there are no puncture wounds, scrapes, lacerations, or bites of any kind on or near my thumb. Not even on my whole right arm. It has been 24 hours now since I injured it and the pain isn't dulling, even with taking ibuprofen, and the swelling has persisted. I can't move my thumb without feeling excruciating pain. Should I get a second opinion or just take the antibiotic and hope for the best?