My skin has got eczema plus infection. i got fucidin ointment and applied to the affected area. then the fluid started coming out. can i still use it?

Depends: Depends on the nature of the infection (dermatitis or subcutaneous involvement). Eczema can be very difficult to control if the infection is not appropriately addressed. Because the description of "fluid coming out" is somewhat unusual, I recommend a virtual consult for a more personalized assessment and bringing this to the attention of your local provider.