在英文中，如果脸上布满了汗珠，可以用以下几种表达方式来描述：
"The person's face was dripping with sweat." 这个人的脸上滴滴答答地流着汗。
"Sweat was pouring down the person's face." 汗水顺着这个人的脸流下来。
"The person's face was covered in sweat." 这个人的脸上满是汗水。
这些表达方式都可以用来描述一个人脸上流着很多汗的情况。来源：汗是人体内分泌的一种液体，当体内温度升高或体内机能过度活跃时，皮肤上的汗腺会分泌汗水，以帮助身体散热。
下面是一些例句：
"I was so nervous during the presentation that my face was dripping with sweat." 我在演讲时非常紧张，脸上滴滴答答地流着汗。
"After the marathon, my face was covered in sweat and I was exhausted." 跑完马拉松后，我的脸上满是汗，感觉很疲乏。
"The heat was so intense that sweat was pouring down my face and neck." 热得简直要炸，汗从我的脸和脖子上流了下来。