My surgeon gave me too big implants. If I replace them with smaller ones, will my pocket be too big and my skin saggy?

I am so very sorry you did not get the results you want. It is too soon to exchange them for something smaller, but the exchange can be done. Your pocket is still forming so it might settle down well with smaller implants. If needed, the lateral pocket can be tightened. Your skin will probably settle down too unless you wait over 6 months to exchange the implants. It also depends upon what size you have now and what size you choose.

Implants often seem larger initially. As time goes in the skin and breast tissue will stretch making them seem smaller. So don’t make a decision on size change yet

The importance of clear and open communications between patient and provider cannot be over emphasized.
Did your provider review before and after pictures with you? How did you or your provider come up with the choice of implant decision?
Ultimately surgeons are responsible for surgical outcomes and patients are responsible for provider selection.
I suggest you have a professional and honest conversation with your provider and ask what they are willing to do to help you.
If you’re not getting the help, you need from your current provider and consider having in person second opinion consultations.
There are two options in regards to revision surgery.
If it’s obvious that revision surgery is going to be done, then there is a window to do this as soon as possible after the first operation before scar tissue begins to form.
If that window is lost and it sometimes better to wait a full six months until scar tissue has matured.
Each plastic surgeon will have their own Thoughts and recommendations of how to manage this.
There are a lot of variables to take in the consideration.
Rushing into final conclusions is often not a good idea so rushing into revision surgery is generally not desirable.
Moving forward with early revision surgery is only appropriate if it is obvious to both provider and patient that revision surgery is inevitable.
Likewise, there is a timeframe at which point early revision surgery is not advisable because early scar tissue is difficult to work with in comparison to scar tissue that has matured.There’s no yes or no answer to your question.
Best,
Mats Hagstrom MD