Swollen foot

I noticed my left foot was swollen when I woke up this morning but I thought it will subside after I rubbed it with some medicated oil. I walked to work and up the slope like any other day without any limp. The swell didn't get better though. I was shocked when I took off my shoes and saw the puffy'ness. It was red and shiny. It wasn't a bit painful when I pressed it slightly in the morning but now it is. My leg felt as if it was tied with a few grams of weights and I walked with a slight limp. Time for me to get a pair of new shoes with adjustable straps or sandals when I returned from work later.