Oh Natalie, you poor thing! From (not so) fond memory, that's just how my cellulitis started - a local area of redness and much pain.
Do you have a temperature?
If it is cellulitis, don't panic - it's a very superficial skin infection and rarely any danger to the implants. But you do need to get some antibiotics ASAP.
Funny, this is the second case we've had post here ....... if that's what it really is, of course.