Can vomiting after I eat be harmful to my breast augmentation?

The strain from vomiting can be problematic with regard to healing tissues and risk of bleeding. I encourage you to discuss your situation with your surgeon. Anti nausea medication may be indicated.

This issue should not be a huge problem, but it does have at least some potential to stir up bleeding in your wound.  I would discuss with your surgeon.

Anything that leads to straining whether it be through strenuous exercise of vomiting can momentarily raise the blood pressure.  These spikes in blood pressure do raise concerns of possible bleeding from recently cauterized vessels.  All this being said, there is no precaution you can take other than attempting to manage your GI issues as best as you can.  In all probability, you should be fine.  Although it is not ideal, I would not expect it to affect your outcome especially as you get further and further from your surgery date.  Hope your recovery moves forward smoothly.