Bumps(or warts) on arm??

Can someone pls help, my partner has had these bumps for around and year, they would normally come and go and we thought it was mosquitos but it’s winter now and they have now just stayed on the arm instead of either popping or fading away. Occasionally they itch or hurt, they are able to be popped and just clear liquid comes out. He does not have eczema or any allergies we know of. He is actively at a gym and often sweaty and touching other sweaty people (involves getting very close to the other person) he is very clean and takes showers every day but I’m so curious what this could be or what could get rid of them. He is male and 20 and only sort of allergy is lactose intolerance ALSO, it is ONLY on his arms, like nowhere else just shoulder and arms