Pepper's Foot Now Hurt, Swollen

Pepper was out catting for about 1 1/2 days - the weather warmed up here. He came home last night, ate and then went to bed... later that evening he got back up to eat again and I noticed him hobbling and not putting pressure on his left foot - the same foot that was hurt on Nut-Nut a few days ago. Well,  Pepper's foot is swollen this morning. I still find it highly suspicious that 2 of my cats (Nut-Nut and now Pepper), both within about a week of each other, having their one of their front paws hurt and swollen. 3 to 3 1/2 years I've been with these cats and this has NEVER happened before --- now 2 of them in about a weeks time.

I'm VERY SUSPICOUS of this...