Left my cup in the sun for 2 months, did I damage it?

I put my Fleurcup on a windowsill in my conservatory to try and bleach some of the stains out, and I put it in a clear plastic box behind the blinds so my cat wouldn't use it as a chew toy. In hindsight, putting it behind the blinds wasn't such a good idea as I promptly forgot it was there, and it remained on the windowsill for the next 2 months (yay irregular cycles!). When I found it today I noticed there was some discolouration at the bottom of the stem and it was a little tacky, both of which have gone away with washing, but there's also a smell there (it doesn't smell like something organic that's gone off, it smells vaguely plastic-y/rubbery) that hasn't gone away. I've had it for less than 2 years. Is it possible the heat/light has degraded the silicone? Do I need to buy a new cup?