IME Blue Lotus should have no diminishing effects on smoking DMT, I use it every time I smoke my changa on a bed of blue lotus and has never had a detrimental effect, I suspect the frequency you are smoking it will have more of an inhibiting effect than anything to do with blue lotus.
My advice would be to take a break for a week or two then give it another go.
LamVamRamYamHamKshamOm