\[ y'(x)=\frac {2 a}{x \left (-8 a^2+2 a x y(x)^2-x y(x)\right )} \] ✓ Mathematica : cpu = 0.232475 (sec), leaf count = 39
\[\text {Solve}\left [\frac {y(x)^2 e^{-4 a y(x)}}{8 a}-\frac {e^{-4 a y(x)}}{2 x}=c_1,y(x)\right ]\] ✓ Maple : cpu = 0.367 (sec), leaf count = 28
\[ \left \{ {\it \_C1}+{\frac {-x \left ( y \left ( x \right ) \right ) ^{2}+4\,a}{{{\rm e}^{4\,ay \left ( x \right ) }}x}}=0 \right \} \]