Hi
It's a challenging surgery that both my close girlfriends have had before. I actually helped guide them through their recovery and assisted them in getting back to their workout routines. You'll definitely need to modify how you perform certain exercises as you adapt to the implants.
Your post-surgery recovery will require daily self-massage that should be done lightly, as instructed by your surgeon, for the first few months (You being 13 weeks are probably doiung this already). Continuing this prior to and after training for the first year can be helpful.
To help with the swelling which may take over six months to subside after surgery, it's normally recommended to work on chest exercises, especially on hammer strength type equipment that are "unilateral" or dumbbell work. This option will allow you to use perfect form and help rekindle the lost muscle from your time off. It will also require you to stabilise and keep the core tight/engaged, which is important since you will be carrying more mass due to the implants on your upper body.
It's best to avoid any exercises that require you to "lean into" the bench, such as various back and shoulder options, as you need more time to heal. You will want to use variations for back exercises that will target areas that will assist you in carrying your new upper-body mass.
When working out, be mindful of not going too heavy and concentrate on volume, focusing on the actual contraction of the muscle you are targeting, especially during chest exercises. Using too heavy a weight and/or some exercises such as "weighted-flys" may cause shifting of the implant, making it harder to fix the issue since the implant is under the muscle.
Take it slow and use this time to work on balancing your body, especially your shoulders, back, legs, and glutes, as the implants will give your upper body more "depth." Ensuring that you stay balanced with the width is important, whether you're a competitor or just looking to achieve a particular look.
Best wishes on your journey!