Visible indent where pec muscle ends. Any suggestions?

Hello!One week post surgery is too early to determine outcome. If the implants are round implants, many surgeons recommend massage to soften scar tissue around the implant and allow for more space, to minimize compression. You should discuss your concerns with your surgeon who should provide options to you to optimize your recovery.Best of luck!

Without a picture it is hard to give an opinion but if the origin of the muscle is cut  to the sternum and the implant does not move inside to fill out this space a dent can occur. If it persists, placing the implant above this muscle will solve this. Good luck. 

It may be related to the release of the muscle, but may improve with time as the implant settles into the pocket. If concerned review with your surgeon.

without a picture it's difficult to assess.  You are also very early post op.  Its best to follow up with your surgeon.  But most often things soften and improve over the first few months as the breast implants descend and settle into position.