The bumps on knees could possible be razor burn tho.

I have something simular. I thought mine were bites. I had two on the back of my leg and one on my ankle. I piped one and saw the clear fluid like water come out. This made the itching stop so I did it to the others. Then I noticed the next day like three more around the one on my thigh and one nexto to the one on my ankle. I popped them too cause thy itched like crazy! The next few days the one on my thigh became like ten others so instopped popping them worried I was causing them to spread. They're are so many the cluster now looks like one big bump with a few scattered around it. I tried ointments and stuff the past like 4 days but no improvement. It's not spreading at as fast of a pace as when It did when I popped them but I think they are still spreading. I am putting steroid cream on it starting tonight. I'll update if it helps. Please let me know what your doc says.

Went to the doctor today, found out I have hand foot and mouth disease. Its an extraordinarily itchy virus that'll go away on its own eventually, until then, i was given steroid cream to help w/ redness and the itching.
She said the redness on my knees and elbows was most likely caused by scratching foot than scratching knee, because it spreads fairly easily apparently. ><