How to refresh an object or indiactor ?

[[Deleted]]

//+------------------------------------------------------------------ +
//| //
//| // How to draw a horizontal line with the lowest price within a given minutes ?
// and follow the PRICE change ?

//+------------------------------------------------------------------ +
#property copyright "Copyright"
#property link "MT4"

#property indicator_chart_window

extern int StartBar = 0;
extern int BarsBack = 15; // Use this indicator on M1 chart, here I want to get the lowest price in the past 15 minutes.

int init()
{
ObjectsDeleteAll();
// WindowRedraw();
return(0);
}

int deinit()
{

ObjectsDeleteAll();
// WindowRedraw();

return(0);
}

int start()
{

double StartPrice;
string Temp,TempAn;


int Lowest_bar = 0;
int Highest_bar = 0;

double Highest_point = 0;
double Lowest_point = 0;

RefreshRates();

Lowest_bar = iLowest(NULL,0,MODE_LOW,BarsBack,StartBar);
Highest_bar = iHighest(NULL,0,MODE_HIGH,7*BarsBack,StartBar);

Highest_point=High[Highest_bar];
Lowest_point=Low[Lowest_bar];



// Draw line

Temp= "LowestLine";
if(ObjectFind(Temp) != 0)
{
ObjectCreate(Temp,OBJ_HLINE,0,0,Lowest_point);
ObjectSet(Temp,OBJPROP_STYLE,STYLE_DOT);
ObjectSet(Temp,OBJPROP_COLOR,Blue);
ObjectSet(Temp,OBJPROP_WIDTH,1);
WindowRedraw();
}

Temp= "HighestLine";
if(ObjectFind(Temp) != 0)
{
ObjectCreate(Temp,OBJ_HLINE,0,0,Highest_point);
ObjectSet(Temp,OBJPROP_STYLE,STYLE_DOT);
ObjectSet(Temp,OBJPROP_COLOR,Blue);
ObjectSet(Temp,OBJPROP_WIDTH,1);
WindowRedraw();
}
// Draw line ----END



// Draw text on line

TempAn=DoubleToStr(Lowest_point,5);
if(ObjectFind(TempAn) != 0)
{
ObjectCreate(TempAn,OBJ_TEXT,0,Time[90],Lowest_point);
ObjectSetText(TempAn,"This is the lowest point line ",10,"Arial",Blue);
WindowRedraw();
}

return(0);
}

For instance, I want to draw a horizontal line with the lowest price in the past 15 minuts on the M1 chart,

If the trend continuely goes down on M1 chart, the line should accordingly move to the new lowest price.

My meanings is the line should be drawn with the lowest price in the past 15 minutes,if the current bar is the lowest,then the line should be drawn using this the new lowest price.

I hope my statement is clear .

But,now it does not move to the new lowest point.

Is there anyone hlep to fix it, thank you !