Is this blister on my incision line something to worry about? (Photos)

Your incisions all look like one might expect them to look after removing the steri- strips. Steri-strips are great for sealing the incisions, but they do sometimes result in blisters. Most of the time, these blisters will heal themselves. From your photos, your blisters look fairly minor. I suspect they will heal fine. You should check with your treating board certified plastic surgeon, however,  I would not recommend starting the silicone gel sheeting until the blisters have heeled themselves. It is difficult to see the sutures in your pictures. However, I suspect that what your experiencing are dissolving sutures. Therefor, they don't need to be removed or pulled out. Some dissolving sutures poking out is normal. A slight opening where your three incisions come together is also fairly typical part of the healing process.