I am 3 months post-op breast uplift and reduction- red breasts and spider veins, is this normal? (Photos)

Based on the photo, it seems you have some hypertrophic scarring and inflammation.  Redness and warmth is alway concerning for a possible infection. Though it is difficult to tell with the photo, I would recommend you make an appointment to see your plastic surgeon as soon as possible for an evaluation.

It is hard to tell from the photo if you are developing an infection. Redness is a common manifestation of scar healing. However, tenderness and increased warmth over the area of the scar may present infection. To rule this out, it is best to schedule an appointment with your surgeon. Scars could take up to a year or more to fully mature, and you are still early in the healing process.

Hi and thanks for sharing your story,
Your scars look a little thickened and red - this is know as hypertrophic scarring and is not an uncommon finding following breast reduction surgery.
The reason for this scarring is usually multifactorial and the fact that it happens in some women and not others usually suggest that some women are just more prone to this type of scarring than others.
But don't lose hope - it is still very early in your post-operative course - scars can take up to 12 months to fully mature.
Talk to your PS about your concerns and enquire as to what scar treatment that they recommend. I usually suggest my patients trial regular scar massage using an emollient of their choice and consider the use of silicone sheeting to try and flatten out some of those thicker scars - if this doesn't yield any results after a few months, you can ask your PS about steroid injections.
Good luck