itchy nipples when lifting weights

[Ripped Mass]

I am nearly 6 weeks post op and am pretty much back at full strength at the gym. However when I am doing my upper body (arms, chest, anything really) my nipples and the area around them get really itchy and continue for at least 4 or 5 hours after I get home. Does this happen to anyone else? Should I be concerned my gland might be growing back or could possibly just be the blood flow and tissue getting stimulated in that area as the feeling in them comes back as most of that area is still pretty numb? I am getting a little paranoid and cannot stop checking my nips for lumps I do not want them to come back!